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Not supported with pagination yet | Which correctly shows the title of a movie? | [
"\"Over the Hedge\"",
"***Over the Hedge***"
] | 1 | closed choice | grade9 | language science | punctuation | Formatting | Formatting titles | The title of a book, movie, play, TV show, magazine, or newspaper should be in italics. If you write it by hand, it can be underlined instead.
A Midsummer Night's Dream
The title of a poem, song, article, or short story should be in quotation marks.
"You Are My Sunshine" | A movie should be in italics.
The correct title is **Over the Hedge**. |
|
In this experiment, which were part of a control group? | [
"the mint plants that did not get earthworms",
"the mint plants that got earthworms"
] | 0 | The passage below describes an experiment.
Zeke grew ten on his back porch. He grew each plant in its own pot. Zeke noticed that his plants did not grow many leaves, and he wanted to see if earthworms could help them grow more.
Zeke divided his ten plants into two equal groups. He added three earthworms each to the soil in five of the pots. He did not add any earthworms to the other five pots. Two months later, he counted the number of leaves on each of the ten plants.
Figure: mint plants. | closed choice | grade7 | natural science | science-and-engineering-practices | Designing experiments | Identify control and experimental groups | Experiments have variables, or parts that change. You can design an experiment to investigate whether changing a variable between different groups has a specific outcome.
For example, imagine you want to find out whether adding fertilizer to soil affects the height of pea plants. You could investigate this question with the following experiment:
You grow one group of pea plants in soil with fertilizer and measure the height of the plants. This group shows you what happens when fertilizer is added to soil. Since fertilizer is the variable whose effect you are investigating, this group is an experimental group.
You grow another group of pea plants in soil without fertilizer and measure the height of the plants. Since this group shows you what happens when fertilizer is not added to the soil, it is a control group.
By comparing the results from the experimental group to the results from the control group, you can conclude whether adding fertilizer to the soil affects pea plant height. | In this experiment, Zeke investigated whether adding earthworms to soil affects how many leaves grow on mint plants. There were no earthworms in the soil of the mint plants that did not get earthworms. So, they were part of a control group. |
|
Based on the continuum scale, which planet is larger than Mars? | [
"Mercury",
"Earth"
] | 1 | This continuum scale shows the sizes of the inner planets of our solar system. | closed choice | grade5 | language science | writing-strategies | Visual elements | Read graphic organizers | A graphic organizer is a chart or picture that shows how ideas, facts, or topics are related to one another.
When you read, look for graphic organizers included in the text. You can use these images to find key information. You can also create your own graphic organizers with information that you've read. Doing this can help you think about the ideas in the text and easily review them.
When you write, you can use graphic organizers to organize your thoughts and plan your writing. | A continuum scale compares things by ordering them along a line. This continuum scale shows the sizes of the inner planets of our solar system.
Smaller planets are shown to the left. Larger planets are shown to the right. Earth is shown farther to the right than Mars. So, Earth is larger than Mars. |
|
Which better describes the Kermadec Arc ecosystem? | [
"It has no sunlight. It also has many large swimming organisms.",
"It has no sunlight. It also has organisms that crawl or stick to the ground."
] | 1 | Figure: Kermadec Arc.
The Kermadec Arc is a deep sea ecosystem in the southern Pacific Ocean. | closed choice | grade3 | natural science | biology | Ecosystems | Describe ecosystems | An ecosystem is formed when living and nonliving things interact in an environment. There are many types of ecosystems. Here are some ways in which ecosystems can differ from each other:
the pattern of weather, or climate
the type of soil or water
the organisms that live there | The deep sea is a type of ecosystem. Deep sea ecosystems have the following features: water at the bottom of the ocean, no sunlight, and organisms that crawl or stick to the ground. So, the Kermadec Arc has no sunlight. It also has organisms that crawl or stick to the ground. |
|
What is the capital of Michigan? | [
"Detroit",
"Lansing",
"Des Moines",
"Lincoln"
] | 1 | closed choice | grade5 | social science | geography | State capitals | Identify state capitals of the Midwest | Lansing is the capital of Michigan. |
|||
Not supported with pagination yet | Is the following trait inherited or acquired?
Kimberly has a scar on her right ankle. | [
"inherited",
"acquired"
] | 1 | Hint: Most scars are caused by accidents during a person's life. | closed choice | grade3 | natural science | biology | Heredity | Identify inherited and acquired traits | Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways.
Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned.
Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Children do not inherit their parents' acquired traits. | Children do not inherit their parent's scars. Instead, scars are caused by the environment. People can get scars after they get hurt. So, having a scar is an acquired trait. |
Not supported with pagination yet | What information supports the conclusion that Elise inherited this trait? | [
"Elise's neighbor also has straight hair.",
"Elise's biological parents have red hair. Elise also has red hair.",
"Elise's biological mother often wears her straight hair in a ponytail."
] | 2 | Read the description of a trait.
Elise has straight hair. | closed choice | grade8 | natural science | biology | Genes to traits | Inherited and acquired traits: use evidence to support a statement | Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways.
Inherited traits are passed down from biological parents to their offspring through genes. Genes are pieces of hereditary material that contain the instructions that affect inherited traits. Offspring receive their genes, and therefore gain their inherited traits, from their biological parents. Inherited traits do not need to be learned.
Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Parents do not pass acquired traits down to their offspring. | |
Not supported with pagination yet | How long does it take to tie your shoes? | [
"27 seconds",
"27 hours"
] | 0 | Select the better estimate. | closed choice | grade2 | natural science | units-and-measurement | Units and measurement | Choose units of time | Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means.
Imagine being told that the bus leaves in 7. You might be thinking, 7 what? Does the bus leave in 7 minutes? 7 seconds?
The number 7 on its own does not give you much information about when the bus is leaving. That is because the units are missing.
Time is usually measured in units of seconds, minutes, or hours. It takes about 1 second to sneeze and 1 minute to get dressed in the morning. It takes about 1 hour to bake a pie in the oven.
There are 60 seconds in 1 minute. So, 1 second is much less than 1 minute.
There are 60 minutes in 1 hour. So, 1 minute is much less than 1 hour. | The better estimate for how long it takes to tie your shoes is 27 seconds.
27 hours is too slow. |
Not supported with pagination yet | What information supports the conclusion that Harry acquired this trait? | [
"Harry's scar was caused by an accident. He cut his arm when he fell off his bicycle.",
"Some scars fade more quickly than others."
] | 0 | Read the description of a trait.
Harry has a scar on his right arm. | closed choice | grade5 | natural science | biology | Traits and heredity | Inherited and acquired traits: use evidence to support a statement | Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways.
Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned.
Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. | |
Think about the magnetic force between the magnets in each pair. Which of the following statements is true? | [
"The strength of the magnetic force is the same in both pairs.",
"The magnetic force is weaker in Pair 2.",
"The magnetic force is weaker in Pair 1."
] | 0 | The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material. | closed choice | grade4 | natural science | physics | Magnets | Compare strengths of magnetic forces | Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart.
These pulls and pushes between magnets are called magnetic forces. The stronger the magnetic force between two magnets, the more strongly the magnets attract or repel each other. | Distance affects the strength of the magnetic force. But the distance between the magnets in Pair 1 and in Pair 2 is the same.
So, the strength of the magnetic force is the same in both pairs. |
|
Not supported with pagination yet | Which logical fallacy is used in the text?
Senator King announced today that she plans to cut funding to early childhood education programs. The last thing we need is a government official who hates children! | [
"bandwagon fallacy: the assumption that the popular choice is automatically correct",
"straw man: a misrepresentation of an opponent's position that makes it easier to argue against"
] | 1 | closed choice | grade7 | language science | writing-strategies | Developing and supporting arguments | Classify logical fallacies | A strong argument uses valid reasoning and logic in support of a claim. When an argument or claim introduces irrelevant information or misrepresents the issues at hand, it may be committing a logical fallacy. Logical fallacies can hurt a writer's credibility and can lead readers to draw false conclusions.
A logical fallacy may present irrelevant information:
Fallacy | Description
ad hominem | a personal attack meant to discredit one's opponent
appeal to nature | an argument that assumes the natural choice is always the best choice
bandwagon fallacy | an argument that assumes the popular choice is always the best choice
circular reasoning | an argument that supports a claim with the claim itself
guilt by association | an unfair negative association with another person or group that is intended to discredit someone or something
red herring | the use of a completely unrelated topic in support of a claim
A logical fallacy may misrepresent the issues at hand:
Fallacy | Description
false causation | the assumption that because two things happened together, one caused the other
false dichotomy | an argument that presents only two choices when more options exist
hasty generalization | a very broad claim based on very little evidence
straw man | a misrepresentation of an opponent's position that makes it easier to argue against
| The text argues that Senator King hates children, because she wants to cut education funding. However, the fact that Senator King wants to cut education funding doesn't necessarily suggest that she hates children. This illustrates a type of logical fallacy known as a straw man. |
|
Think about the magnetic force between the magnets in each pair. Which of the following statements is true? | [
"The magnitude of the magnetic force is smaller in Pair 1.",
"The magnitude of the magnetic force is the same in both pairs.",
"The magnitude of the magnetic force is smaller in Pair 2."
] | 2 | The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different sizes and shapes. | closed choice | grade7 | natural science | physics | Velocity, acceleration, and forces | Compare magnitudes of magnetic forces | Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces.
The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other.
You can change the magnitude of a magnetic force between two magnets by using magnets of different sizes. The magnitude of the magnetic force is smaller when the magnets are smaller. | The magnets in Pair 1 attract. The magnets in Pair 2 repel. But whether the magnets attract or repel affects only the direction of the magnetic force. It does not affect the magnitude of the magnetic force.
Magnet sizes affect the magnitude of the magnetic force. Imagine magnets that are the same shape and made of the same material. The smaller the magnets, the smaller the magnitude of the magnetic force between them.
Magnet A is the same size in both pairs. But Magnet B is smaller in Pair 2 than in Pair 1. So, the magnitude of the magnetic force is smaller in Pair 2 than in Pair 1. |
|
Not supported with pagination yet | Select the one animal that has all of the amphibian traits listed above. | [
"Bengal tigers are one of the world's largest living cats. They have black, white, and orange fur. Female Bengal tigers feed their offspring milk. Male Bengal tigers can be almost twice as large as females!",
"Japanese tree frog tadpoles hatch from eggs without shells. The tadpoles live underwater. After some time, they grow legs and crawl onto land. Adult Japanese tree frogs have moist, smooth green skin."
] | 1 | Amphibians are a group of animals with similar traits. The following traits can be used to identify amphibians:
They spend part of their lives in water and part on land.
They have moist skin.
They make eggs with no shells. Observe the animals and read the descriptions. | closed choice | grade5 | natural science | biology | Classification | Use evidence to classify mammals, birds, fish, reptiles, and amphibians | Scientists sort animals with similar traits into groups. This is called classification. Classification helps scientists learn about how animals live.
How do scientists classify animals? First, they make observations about an animal. Scientists observe the animal's traits, including its body parts and behavior. Then, scientists compare the animal's traits to other animals' traits. Scientists classify animals with similar traits into a group. | To decide if an animal is part of a group, look at the traits of the group.
Amphibians have the following traits:
They spend part of their lives in water and part on land.
They have moist skin.
They make eggs with no shells.
Compare each animal's traits to the group's traits. Select the animal with traits similar to the group's traits.
A Bengal tiger has the following traits:
It feeds its offspring milk.
It has hair.
A Bengal tiger does not have all of the traits of an amphibian. A Bengal tiger is a mammal.
A Japanese tree frog has the following traits:
It spends part of its life in water and part on land.
It has moist skin.
It makes eggs with no shells.
A Japanese tree frog has the traits of an amphibian. A Japanese tree frog is an amphibian. |
Not supported with pagination yet | The movers lift the boxes at the same speed. Which box is lifted with a larger force? | [
"a box holding 23 pounds",
"a box holding 21 pounds"
] | 0 | Two movers are putting heavy boxes into their truck. The boxes are the same shape and size. Each mover lifts one box up into the truck at a time. | closed choice | grade2 | natural science | physics | Force and motion | How do mass and force affect motion? | A force is a push or a pull.
A force can make an object start moving or stop an object that is moving. A force can also make an object speed up, slow down, or change direction.
Forces can be different sizes.
Think about trying to move a heavy object and a light object. Imagine you want to move them at the same speed. You will need to use a larger force to move the heavy object. | Look for the box that is heavier.
A box holding 23 pounds is heavier than a box holding 21 pounds. So, the box holding 23 pounds needs a larger force to start moving upward at the same speed as the other box. |
Which animal's mouth is also adapted for gnawing? | [
"cougar",
"Podolsk mole rat"
] | 1 | Brown rats eat plant matter, such as leaves, stems, and seeds. They eat by biting off small pieces at a time, or gnawing. The rat's mouth is adapted for gnawing.
Figure: brown rat. | closed choice | grade3 | natural science | biology | Adaptations | Animal adaptations: beaks, mouths, and necks | An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The shape of an animal's mouth is one example of an adaptation. Animals' mouths can be adapted in different ways. For example, a large mouth with sharp teeth might help an animal tear through meat. A long, thin mouth might help an animal catch insects that live in holes. Animals that eat similar food often have similar mouths. | Look at the picture of the brown rat.
The brown rat has large front teeth. Its mouth is adapted for gnawing. The large front teeth can help the brown rat break off pieces of food that it can swallow.
Now look at each animal. Figure out which animal has a similar adaptation.
The Podolsk mole rat has large front teeth. Its mouth is adapted for gnawing.
The cougar does not have large front teeth. Its mouth is not adapted for gnawing. The cougar uses its mouth to tear through meat. |
|
Which property do these two objects have in common? | [
"yellow",
"stretchy"
] | 0 | Select the better answer. | closed choice | grade2 | natural science | physics | Materials | Compare properties of objects | An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells.
Different objects can have the same properties. You can use these properties to put objects into groups. | Look at each object.
For each object, decide if it has that property.
Yellow is a color.
This color is yellow. Both objects are yellow.
A stretchy object gets longer when you pull on it. The gold nugget is not stretchy.
The property that both objects have in common is yellow. |
|
Not supported with pagination yet | Complete the sentence so that it uses personification.
The sleek new race car () its driver. | [
"appealed to",
"grinned at"
] | 1 | closed choice | grade10 | language science | writing-strategies | Creative techniques | Use personification | Personification is giving human characteristics to nonhuman things. It is a figure of speech that can be used to make writing more interesting or to emphasize a point.
The trees danced in the wind.
The word danced describes the trees as if they were people. Unlike people, however, trees can't actually dance. Instead, the personification suggests that the trees are moving. | Complete the sentence with the phrase grinned at. It describes the race car as if it were a happy person. |
|
Not supported with pagination yet | Which type of sentence is this?
As Manuel sat down on the rickety old chair, it abruptly collapsed beneath him. | [
"compound",
"simple",
"compound-complex",
"complex"
] | 3 | closed choice | grade12 | language science | grammar | Phrases and clauses | Is the sentence simple, compound, complex, or compound-complex? | A clause is a group of words that contains both a subject and a predicate.
An independent clause is a complete thought that can stand alone as a sentence. A dependent clause (or subordinate clause) is not a complete thought and cannot stand alone as a sentence.
the oranges on our tree are ripe
The clause can stand alone. It is independent.
after we pick up Kevin from work
The clause cannot stand alone. It is dependent.
A simple sentence is made up of a single independent clause.
Ben and I spent all day relaxing by the pool.
Some simple sentences have introductory phrases, but the introductory phrase is part of the predicate.
In the winter, Ben usually wears his heavy coat.
Ben usually wears his heavy coat in the winter.
A compound sentence is made up of two independent clauses joined by a coordinating conjunction such as and, but, or, or so.
We saw the flash of lightning, and seconds later we heard a rumble of thunder.
A complex sentence is made up of an independent clause and a dependent clause. The dependent clause in a complex sentence usually begins with a subordinating conjunction or relative pronoun. Subordinating conjunctions include after, although, as, because, before, if, since, unless, until, when, and while. Relative pronouns include that, which, who, whom, or whose.
If she ever gets the chance, Terri would love to visit the Egyptian pyramids.
During his trip to Italy, Tony visited the Trevi Fountain, which is in Rome.
A compound-complex sentence is made up of two or more independent clauses and one or more dependent clauses.
After Samantha left work, she stopped at the bank, and then she went to the gym.
Sometimes a dependent clause in a complex or compound-complex sentence can interrupt an independent clause.
Orcas that are kept in captivity often have bent dorsal fins. | The sentence is complex. It is made up of an independent clause and a dependent clause. The dependent clause begins with the subordinating conjunction as.
As Manuel sat down on the rickety old chair, it abruptly collapsed beneath him. |
|
What is the capital of Maryland? | [
"Annapolis",
"Athens",
"Davenport",
"Dallas"
] | 0 | closed choice | grade3 | social science | geography | State capitals | Identify state capitals of the Northeast | Annapolis is the capital of Maryland. |
|||
Which bird's beak is also adapted to filter through mud? | [
"common nighthawk",
"black swan"
] | 1 | Northern pintails eat plants that grow underwater or in mud. The shape of the 's beak is adapted to filter through mud for food.
The gathers muddy water in its beak and then pushes it out through gaps along the sides. Bits of food, such as plant roots, are left behind inside the pintail's beak.
Figure: northern pintail. | closed choice | grade5 | natural science | biology | Adaptations | Animal adaptations: beaks, mouths, and necks | An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The shape of a bird's beak is one example of an adaptation. Birds' beaks can be adapted in different ways. For example, a sharp hooked beak might help a bird tear through meat easily. A short, thick beak might help a bird break through a seed's hard shell. Birds that eat similar food often have similar beaks. | Look at the picture of the northern pintail.
The northern pintail has a wide, flat beak. Its beak is adapted to filter through mud. The northern pintail gathers muddy water in its beak. Then, it pushes the water out through gaps along the sides of the beak. Bits of food, such as plant roots, are left behind inside the pintail's beak.
Now look at each bird. Figure out which bird has a similar adaptation.
The black swan has a wide, flat beak. Its beak is adapted to filter through mud.
The common nighthawk has a short, thin beak. Its beak is not adapted to filter through mud. The common nighthawk uses its beak to eat insects and other small invertebrates. |
|
Which better describes the tide pool ecosystems in Tongue Point Marine Life Sanctuary? | [
"It has daily flooding and draining of seawater. It also has water that is rich in nutrients.",
"It has no sunlight. It also has daily flooding and draining of seawater."
] | 0 | Figure: Tongue Point Marine Life Sanctuary.
Tongue Point Marine Life Sanctuary is in western Washington State. The park is on the coast of the Pacific Ocean. It has many tide pool ecosystems. | closed choice | grade3 | natural science | biology | Ecosystems | Describe ecosystems | An ecosystem is formed when living and nonliving things interact in an environment. There are many types of ecosystems. Here are some ways in which ecosystems can differ from each other:
the pattern of weather, or climate
the type of soil or water
the organisms that live there | A tide pool is a type of ecosystem. Tide pool ecosystems have the following features: daily flooding and draining of seawater, water that is rich in nutrients, and many different types of organisms. So, the tide pool ecosystems in Tongue Point Marine Life Sanctuary have daily flooding and draining of seawater. They also have water that is rich in nutrients. |
|
Not supported with pagination yet | Choose the poem that has a regular rhythm, or a pattern of sound like a beat. | [
"I breathed a song into the air,\nIt fell to earth, I knew not where;\nFor who has sight so keen and strong\nThat it can track the flight of song?",
"I thought:\nThe moon,\nShining upon the many steps of the palace before me,\nShines also upon the checkered rice fields\nOf my native land."
] | 0 | Adapted from Henry Wadsworth Longfellow, "The Arrow and the Song" and adapted from Amy Lowell, "From China" | closed choice | grade4 | language science | reading-comprehension | Poetry elements | Identify elements of poetry | Poetry is a special kind of writing. It has many elements that make it different from ordinary writing. Knowing these elements can help you talk about poetry, understand it better, and enjoy it more.
A poem rhymes when it has a pattern of words that end in the same sound.
End rhyme is when the rhymes appear at the end of a poem's lines.
Little Betty Blue,
Lost her holiday shoe.
—From Mother Goose
Internal rhyme is when at least one of the rhyming words appears inside the poem's lines.
Sweet dreams of pleasant streams.
—From William Blake, "A Cradle Song"
Rhythm is the pattern of strong and weak syllables, or stress, in a poem. You can recognize rhythm in a poem by listening to how it sounds. Poems with regular rhythm have a beat, like in music.
He watches from his mountain walls,
And like a thunderbolt he falls.
—From Alfred, Lord Tennyson, "The Eagle"
The syllables in bold are strong. We say them with more force than the other syllables. In this poem, every weak syllable is followed by a strong syllable. Each line sounds like da-DUM da-DUM da-DUM da-DUM. To better hear the rhythm, try reading it aloud while clapping on each strong syllable.
Free verse is when a poem has neither a regular rhythm nor a rhyme pattern.
The old bridge has a wrinkled face.
He bends his back
For us to go over.
—From Hilda Conkling, "The Old Bridge"
The syllables in bold are strong. You can see this poem does not have a regular rhythm. It also doesn't have a rhyme pattern.
Repetition is when words, phrases, or whole lines are repeated.
The dainty flying squirrel
In vest of shining white,
In coat of silver gray,
And vest of shining white.
—Adapted from Mary E. Burt, "The Flying Squirrel"
Alliteration is when beginning consonant sounds are repeated in words that are close together.
Where the wild men watched and waited
Wolves in the forest, and bears in the bush.
—From Bayard Taylor, "A Night with a Wolf"
Onomatopoeia is when language sounds like what it talks about.
Sometimes the onomatopoeia uses made-up words:
Tlot-tlot! tlot-tlot! Had they heard it? The horse hoofs ringing clear.
—From Alfred Noyes, "The Highwayman"
Sometimes the onomatopoeia uses real words:
Hark! the honey bee is humming.
—From Mary Howitt, "The Voice of Spring" | This poem has a regular rhythm, or a pattern of sound like a beat. The parts in bold show the strong syllables. The pattern is a weak syllable followed by a strong syllable. It sounds like da-DUM da-DUM.
That it can track the flight of song? |
Which of these states is farthest west? | [
"Connecticut",
"Maine",
"Pennsylvania",
"Vermont"
] | 2 | closed choice | grade2 | social science | geography | Geography | Read a map: cardinal directions | Maps have four cardinal directions, or main directions. Those directions are north, south, east, and west.
A compass rose is a set of arrows that point to the cardinal directions. A compass rose usually shows only the first letter of each cardinal direction.
The north arrow points to the North Pole. On most maps, north is at the top of the map. | To find the answer, look at the compass rose. Look at which way the west arrow is pointing. Pennsylvania is farthest west. |
||
Which property do these three objects have in common? | [
"blue",
"scratchy",
"transparent"
] | 1 | Select the best answer. | closed choice | grade3 | natural science | physics | Materials | Compare properties of objects | An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it.
Different objects can have properties in common. You can use these properties to put objects into groups. | Look at each object.
For each object, decide if it has that property.
You can see clearly through a transparent object. None of the objects are transparent.
A scratchy object is rough and itchy against your skin. All three objects are scratchy.
Blue is a color.
This color is blue. None of the objects are blue.
The property that all three objects have in common is scratchy. |
|
In this food chain, the diatom is a producer. Why? | [
"It eats a consumer.",
"It makes its own food.",
"It eats another organism."
] | 1 | This diagram shows a food chain from a tropical coral reef ecosystem off the coast of Australia. | closed choice | grade5 | natural science | biology | Ecosystems | Identify roles in food chains | Every organism needs food to stay alive. Organisms get their food in different ways. A food chain shows how organisms in an ecosystem get their food.
The food chain begins with the producer. A producer can change matter that is not food into food. Many producers use carbon dioxide, water, and sunlight to make sugar. Carbon dioxide and water are not food, but sugar is food for the producer.
Consumers eat other organisms. There can be several kinds of consumers in a food chain:
A primary consumer eats producers. The word primary tells you that this is the first consumer in a food chain.
A secondary consumer eats primary consumers. The word secondary tells you that this is the second consumer in a food chain.
A tertiary consumer eats secondary consumers. The word tertiary tells you that this is the third consumer in a food chain.
A top consumer is the animal at the top of a food chain. Food chains can have different numbers of organisms. For example, when there are four organisms in the chain, the top consumer is the tertiary consumer. But if there are five organisms in the chain, the top consumer eats the tertiary consumer! | In this food chain, the diatom is a producer because it makes its own food. The diatom uses carbon dioxide, water, and sunlight to make its own food. |
|
Not supported with pagination yet | Which type of sentence is this?
As Ryan sat down on the rickety old chair, it abruptly collapsed beneath him. | [
"complex",
"compound-complex",
"simple",
"compound"
] | 0 | closed choice | grade11 | language science | grammar | Phrases and clauses | Is the sentence simple, compound, complex, or compound-complex? | A clause is a group of words that contains both a subject and a predicate.
An independent clause is a complete thought that can stand alone as a sentence. A dependent clause (or subordinate clause) is not a complete thought and cannot stand alone as a sentence.
the oranges on our tree are ripe
The clause can stand alone. It is independent.
after we pick up Kevin from work
The clause cannot stand alone. It is dependent.
A simple sentence is made up of a single independent clause.
Ben and I spent all day relaxing by the pool.
Some simple sentences have introductory phrases, but the introductory phrase is part of the predicate.
In the winter, Ben usually wears his heavy coat.
Ben usually wears his heavy coat in the winter.
A compound sentence is made up of two independent clauses joined by a coordinating conjunction such as and, but, or, or so.
We saw the flash of lightning, and seconds later we heard a rumble of thunder.
A complex sentence is made up of an independent clause and a dependent clause. The dependent clause in a complex sentence usually begins with a subordinating conjunction or relative pronoun. Subordinating conjunctions include after, although, as, because, before, if, since, unless, until, when, and while. Relative pronouns include that, which, who, whom, or whose.
If she ever gets the chance, Terri would love to visit the Egyptian pyramids.
During his trip to Italy, Tony visited the Trevi Fountain, which is in Rome.
A compound-complex sentence is made up of two or more independent clauses and one or more dependent clauses.
After Samantha left work, she stopped at the bank, and then she went to the gym.
Sometimes a dependent clause in a complex or compound-complex sentence can interrupt an independent clause.
Orcas that are kept in captivity often have bent dorsal fins. | The sentence is complex. It is made up of an independent clause and a dependent clause. The dependent clause begins with the subordinating conjunction as.
As Ryan sat down on the rickety old chair, it abruptly collapsed beneath him. |
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Not supported with pagination yet | Would you find the word house on a dictionary page with the following guide words?
hello - hurl | [
"yes",
"no"
] | 0 | yes or no | grade4 | language science | reference-skills | Reference skills | Use guide words | Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order.
To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on.
If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed. | Put the words in alphabetical order.
Since house is between the guide words hello - hurl, it would be found on that page. |
|
Which country is highlighted? | [
"New Zealand",
"Papua New Guinea",
"Solomon Islands",
"Australia"
] | 3 | closed choice | grade6 | social science | geography | Oceania: geography | Identify and select countries of Oceania | This country is Australia.
Is Australia a country or a continent?
Both! Australia is a country in Oceania, a region made up of many lands and islands in the Pacific Ocean. Many people say that Australia is the world's smallest continent. But some people call Oceania a continent instead. |
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Not supported with pagination yet | Which is a run-on sentence? | [
"This book explains the difference between cattle and buffalo.",
"It was snowing I wore my black boots."
] | 1 | closed choice | grade3 | language science | writing-strategies | Sentences, fragments, and run-ons | Is it a complete sentence or a run-on? | A sentence is a group of words that forms a complete thought. It has both a subject and a verb.
My friends walk along the path.
A run-on sentence is made up of two sentences that are joined without end punctuation or with just a comma.
I knocked on the door it opened.
It started raining, we ran inside.
To fix a run-on sentence, separate it into two sentences. Add end punctuation after the first sentence, and capitalize the second sentence.
I knocked on the door. It opened.
It started raining. We ran inside.
You can also fix a run-on sentence by rewriting it as a compound sentence. A compound sentence is two sentences joined by a comma and a conjunction such as and, but, or, or so.
I knocked on the door, and it opened.
It started raining, so we ran inside. | It was snowing I wore my black boots is a run-on sentence. It has two sentences that are joined without end punctuation: It was snowing and I wore my black boots. |
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Not supported with pagination yet | Which of the following contains a vague pronoun reference? | [
"Andy accidentally bumped into the waiter, and food splattered all over his shirt.",
"Andy accidentally bumped into the waiter, and food splattered all over Andy's shirt."
] | 0 | closed choice | grade7 | language science | writing-strategies | Pronouns and antecedents | Identify vague pronoun references | When writing, make sure to avoid vague pronoun references. A vague pronoun reference occurs when a pronoun could refer to more than one possible antecedent.
When Lisa and Kim finally landed, she breathed a sigh of relief.
The pronoun she could refer to either Lisa or Kim, so the meaning of the sentence is unclear.
Vague pronoun references can be corrected in one of two ways:
1. Replace the pronoun with its correct antecedent:
When Lisa and Kim finally landed, Lisa breathed a sigh of relief.
2. Rewrite the sentence:
Lisa breathed a sigh of relief when she and Kim finally landed.
A vague pronoun reference also occurs when they, them, their, theirs, it, or its is used without its antecedent.
They say that this nail polish dries in less than five minutes.
The pronoun they is used without its antecedent, so the meaning of the sentence is unclear.
This problem can be fixed by replacing the pronoun with its missing antecedent.
The advertisements say that this nail polish dries in less than five minutes. | The first answer choice contains a vague pronoun reference. The pronoun his could refer to Andy's or the waiter's.
The second answer choice shows a possible correction for the vague pronoun reference. His has been replaced with Andy's.
Andy accidentally bumped into the waiter, and food splattered all over Andy's shirt. |
|
Which animal is also adapted to be camouflaged in a sandy desert? | [
"bearded dragon",
"scarlet snake"
] | 0 | Camels live in dry places such as deserts. The is adapted to be camouflaged in a sandy desert.
Figure: camel. | closed choice | grade4 | natural science | biology | Adaptations | Animal adaptations: skins and body coverings | An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The color, texture, and covering of an animal's skin are examples of adaptations. Animals' skins can be adapted in different ways. For example, skin with thick fur might help an animal stay warm. Skin with sharp spines might help an animal defend itself against predators. | Look at the picture of the camel.
The camel has sand-colored fur covering its skin. It is adapted to be camouflaged in a sandy desert. The word camouflage means to blend in.
Now look at each animal. Figure out which animal has a similar adaptation.
The bearded dragon has a sand-colored body. It is adapted to be camouflaged in a sandy desert.
The scarlet snake has red, black, and white rings on its body. It is not adapted to be camouflaged in a sandy desert. |
|
Select the bird below. | [
"Chinese alligator",
"pelican"
] | 1 | Birds have feathers, two wings, and a beak. A keel-billed toucan is an example of a bird. | closed choice | grade3 | natural science | biology | Classification | Identify mammals, birds, fish, reptiles, and amphibians | Birds, mammals, fish, reptiles, and amphibians are groups of animals. The animals in each group have traits in common.
Scientists sort animals into groups based on traits they have in common. This process is called classification. | A pelican is a bird. It has feathers, two wings, and a beak.
Brown pelicans live near water. They can dive underwater to catch fish.
A Chinese alligator is a reptile. It has scaly, waterproof skin.
Alligators live in and around water. They can live near ponds, rivers, marshes, and lakes. |
|
Which continent is highlighted? | [
"South America",
"Antarctica",
"Africa",
"Asia"
] | 1 | closed choice | grade3 | social science | geography | Geography | Identify oceans and continents | A continent is one of the seven largest areas of land on earth. | This continent is Antarctica. |
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Not supported with pagination yet | Complete the statement. Assume that the scoop of ice cream's mass did not change.
The gravitational potential energy stored between the scoop of ice cream and Earth () as the ice cream dropped toward the ground. | [
"stayed the same",
"increased",
"decreased"
] | 2 | Read the text about an object in motion.
Jason was holding an ice cream cone with two scoops of mint chip ice cream. When he licked the ice cream, a scoop fell off and dropped to the ground. | closed choice | grade7 | natural science | physics | Kinetic and potential energy | Identify changes in gravitational potential energy | Gravitational potential energy is stored between any two objects. So, for every object on or near Earth, there is gravitational potential energy stored between the object and Earth.
The amount of gravitational potential energy stored between an object and Earth depends on the mass of the object. The amount of gravitational potential energy also depends on the distance between the object and the center of Earth. This distance increases when the object moves higher and decreases when the object moves lower.
If the distance between an object and the center of Earth changes, the gravitational potential energy stored between the object and Earth will change. The table below shows how this change can happen.
When an object's mass stays the same and its distance from the center of Earth... | Gravitational potential energy stored between the object and Earth...
increases | increases
decreases | decreases
stays the same | stays the same | Think about how the distance between the scoop of ice cream and the center of Earth changed.
The ground was lower than the ice cream cone. As the scoop of ice cream fell toward the ground, the distance between the scoop and the center of Earth decreased. So, the gravitational potential energy stored between the scoop of ice cream and Earth decreased as the ice cream dropped toward the ground. |
Not supported with pagination yet | Would you find the word dues on a dictionary page with the following guide words?
decline - dignified | [
"no",
"yes"
] | 0 | yes or no | grade5 | language science | reference-skills | Reference skills | Use guide words | Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order.
To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on.
If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed. | Put the words in alphabetical order.
Since dues is not between the guide words decline - dignified, it would not be found on that page. |
|
Not supported with pagination yet | How long is a leather belt? | [
"32 feet",
"32 inches"
] | 1 | Select the better estimate. | closed choice | grade3 | natural science | units-and-measurement | Units and measurement | Choose customary units of distance | Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means.
Imagine being told that a pencil is 8 long. You might be thinking, 8 what? Is the pencil 8 inches long? 8 feet? 8 miles?
The number 8 on its own does not give you much information about the length of the pencil. That is because the units are missing.
Now look at the drawing of the pencil and the ruler. The ruler shows that the units are inches. So, the length of the pencil is 8 inches.
There are 12 inches in 1 foot. So, 1 inch is much shorter than 1 foot.
There are 3 feet in 1 yard. So, 1 foot is shorter than 1 yard. | The better estimate for the length of a leather belt is 32 inches.
32 feet is too long. |
Which material is this aluminum foil made of? | [
"plastic",
"metal"
] | 1 | closed choice | grade2 | natural science | physics | Materials | Identify materials in objects | A material is a type of matter. Wood, glass, metal, and plastic are common materials. | Look at the picture of the aluminum foil.
Aluminum foil is made of metal.
Aluminum foil is made by pressing large blocks of aluminum until they are flat. The blocks of aluminum are large and heavy. They weigh over 10,000 pounds! |
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Not supported with pagination yet | Which word would you find on a dictionary page with the following guide words?
hidden - hurdle | [
"haul",
"hornet"
] | 1 | closed choice | grade7 | language science | reference-skills | Reference skills | Use guide words | Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order.
To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on.
If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed. | Put the words in alphabetical order.
Since hornet is between the guide words hidden - hurdle, it would be found on that page. |
|
What is the name of the colony shown? | [
"Connecticut",
"North Carolina",
"Maryland",
"Indiana"
] | 1 | closed choice | grade7 | social science | us-history | Colonial America | Identify the Thirteen Colonies | The colony is North Carolina. |
|||
Which state is highlighted? | [
"Oregon",
"California",
"Montana",
"Nevada"
] | 2 | closed choice | grade5 | social science | geography | States | Identify the 50 states | This state is Montana. |
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Not supported with pagination yet | Complete the sentence so that it uses personification.
Emily finally found her phone () under the bed. | [
"ringing",
"hiding"
] | 1 | closed choice | grade9 | language science | writing-strategies | Creative techniques | Use personification | Personification is giving human characteristics to nonhuman things. It is a figure of speech that can be used to make writing more interesting or to emphasize a point.
The trees danced in the wind.
The word danced describes the trees as if they were people. Unlike people, however, trees can't actually dance. Instead, the personification suggests that the trees are moving. | Complete the sentence with the word hiding. It describes the phone as if it were a person who is hiding. |
|
Which statement describes the Catoctin Mountain Park ecosystem? | [
"It has only a few types of trees.",
"It has soil that is poor in nutrients."
] | 0 | Figure: Catoctin Mountain Park.
Catoctin Mountain Park is a temperate deciduous forest ecosystem in Maryland. Most of this forest was cut down for its wood in the early 1900s. But since the 1940s, conservation efforts have allowed the forest to return to much of this park. | closed choice | grade8 | natural science | biology | Ecosystems | Describe ecosystems | An environment includes all of the biotic, or living, and abiotic, or nonliving, things in an area. An ecosystem is created by the relationships that form among the biotic and abiotic parts of an environment.
There are many different types of terrestrial, or land-based, ecosystems. Here are some ways in which terrestrial ecosystems can differ from each other:
the pattern of weather, or climate
the type of soil
the organisms that live there | A temperate deciduous forest is a type of ecosystem. Temperate deciduous forests have the following features: warm, wet summers and cold, wet winters, soil that is rich in nutrients, and only a few types of trees. So, the following statements describe the Catoctin Mountain Park ecosystem: warm, wet summers and cold, wet winters, soil that is rich in nutrients, and only a few types of trees. It has only a few types of trees. It has warm, wet summers and cold, wet winters. The following statement does not describe Catoctin Mountain Park: warm, wet summers and cold, wet winters, soil that is rich in nutrients, and only a few types of trees. It has soil that is poor in nutrients. |
|
What is the capital of Vermont? | [
"Olympia",
"Concord",
"Burlington",
"Montpelier"
] | 3 | closed choice | grade3 | social science | geography | State capitals | Identify state capitals of the Northeast | Montpelier is the capital of Vermont. |
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Not supported with pagination yet | Select the one animal that has all of the crustacean traits listed above. | [
"Rock lobsters can live more than 600 feet underwater! They have an exoskeleton and two pairs of antennae.",
"Trichina worms have soft, thin bodies. They have a cylindrical shape and do not have limbs. Trichina worms are not made up of segments. They can infect and feed off of humans, pigs, and other mammals."
] | 0 | Crustaceans are a group of animals with similar traits. The following traits can be used to identify crustaceans:
They have two pairs of antennae.
They have an exoskeleton. Observe the animals and read the descriptions. | closed choice | grade5 | natural science | biology | Classification | Use evidence to classify animals | Scientists sort animals with similar traits into groups. This is called classification. Classification helps scientists learn about how animals live.
How do scientists classify animals? First, they make observations about an animal. Scientists observe the animal's traits, including its body parts and behavior. Then, scientists compare the animal's traits to other animals' traits. Scientists classify animals with similar traits into a group. | To decide if an animal is part of a group, look at the traits of the group.
Crustaceans have the following traits:
They have two pairs of antennae.
They have an exoskeleton.
Compare each animal's traits to the group's traits. Select the animal with traits similar to the group's traits.
A rock lobster has the following traits:
It has two pairs of antennae.
It has an exoskeleton.
A rock lobster has the traits of a crustacean. A rock lobster is a crustacean.
A trichina worm has the following traits:
A trichina worm does not have all of the traits of a crustacean. A trichina worm is a roundworm. |
Not supported with pagination yet | What do these two changes have in common?
filtering air to remove dust and pollen
pouring milk on oatmeal | [
"Both are caused by heating.",
"Both are caused by cooling.",
"Both are only physical changes.",
"Both are chemical changes."
] | 2 | closed choice | grade7 | natural science | chemistry | Chemical reactions | Compare physical and chemical changes | Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule.
In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form different molecules. The types of molecules in matter before and after a chemical change are always different.
Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then link together in a different way to form different molecules. For example, carbon dioxide molecules are formed when paper burns.
In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same.
A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, water vaporizing is a physical change that can be caused by heating. Liquid water and water vapor are made of the same type of matter: water.
The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change. | Step 1: Think about each change.
Filtering air to remove dust and pollen is a physical change. The air flows through the filter, and the pollen and dust stay behind. This separates the mixture of air, pollen, and dust. But separating a mixture does not form a different type of matter.
Pouring milk on oatmeal is a physical change. The oatmeal and milk form a creamy mixture. But making this mixture does not form a different type of matter.
Step 2: Look at each answer choice.
Both are only physical changes.
Both changes are physical changes. No new matter is created.
Both are chemical changes.
Both changes are physical changes. They are not chemical changes.
Both are caused by heating.
Neither change is caused by heating.
Both are caused by cooling.
Neither change is caused by cooling. |
|
Not supported with pagination yet | Which logical fallacy is used in the text?
I'm never setting foot in any seafood restaurant again. We just had a ridiculously overpriced dinner at Cameron's Seafood Hut, and I have no interest in repeating that experience. | [
"circular reasoning: an argument that supports a claim with the claim itself",
"hasty generalization: a very broad claim based on very little evidence"
] | 1 | closed choice | grade6 | language science | writing-strategies | Developing and supporting arguments | Classify logical fallacies | A strong argument uses valid reasoning and logic in support of a claim. When an argument or claim introduces irrelevant information or misrepresents the issues at hand, it may be committing a logical fallacy. Logical fallacies can hurt a writer's credibility and can lead readers to draw false conclusions.
A logical fallacy may present irrelevant information:
Fallacy | Description
ad hominem | a personal attack meant to discredit one's opponent
appeal to nature | an argument that assumes the natural choice is always the best choice
bandwagon fallacy | an argument that assumes the popular choice is always the best choice
circular reasoning | an argument that supports a claim with the claim itself
guilt by association | an unfair negative association with another person or group that is intended to discredit someone or something
red herring | the use of a completely unrelated topic in support of a claim
A logical fallacy may misrepresent the issues at hand:
Fallacy | Description
false causation | the assumption that because two things happened together, one caused the other
false dichotomy | an argument that presents only two choices when more options exist
hasty generalization | a very broad claim based on very little evidence
straw man | a misrepresentation of an opponent's position that makes it easier to argue against
| The text argues that all seafood restaurants are overpriced. However, even though one seafood restaurant was overpriced, that doesn't necessarily mean that all seafood restaurants are overpriced. This illustrates a type of logical fallacy known as a hasty generalization. |
|
Select the fish below. | [
"green chameleon",
"goldfish",
"fruit bat",
"great crested newt"
] | 1 | Fish live underwater. They have fins, not limbs.
Fish are cold-blooded. The body temperature of cold-blooded animals depends on their environment.
A tiger shark is an example of a fish. | closed choice | grade4 | natural science | biology | Classification | Identify mammals, birds, fish, reptiles, and amphibians | Birds, mammals, fish, reptiles, and amphibians are groups of animals. Scientists sort animals into each group based on traits they have in common. This process is called classification.
Classification helps scientists learn about how animals live. Classification also helps scientists compare similar animals. | A green chameleon is a reptile. It has scaly, waterproof skin.
Chameleons eat insects. They use their long, sticky tongues to catch their prey.
A fruit bat is a mammal. It has hair and feeds its young milk.
Fruit bats eat fruit and drink nectar from flowers. They have special teeth to help them bite through fruit skins.
A great crested newt is an amphibian. It has moist skin and begins its life in water.
Some newts live in water. Other newts live on land but lay their eggs in water.
A goldfish is a fish. It lives underwater. It has fins, not limbs.
Goldfish are popular as pets in many countries today. They were first kept as pets by people in ancient China. |
|
Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature? | [
"sample A",
"neither; the samples have the same temperature",
"sample B"
] | 0 | The diagrams below show two pure samples of gas in identical closed, rigid containers. Each colored ball represents one gas particle. Both samples have the same number of particles. | closed choice | grade6 | natural science | physics | Particle motion and energy | Identify how particle motion affects temperature and pressure | The temperature of a substance depends on the average kinetic energy of the particles in the substance. The higher the average kinetic energy of the particles, the higher the temperature of the substance.
The kinetic energy of a particle is determined by its mass and speed. For a pure substance, the greater the mass of each particle in the substance and the higher the average speed of the particles, the higher their average kinetic energy. | Each particle in the two samples has the same mass, but the particles in sample A have a higher average speed than the particles in sample B. So, the particles in sample A have a higher average kinetic energy than the particles in sample B.
Because the particles in sample A have the higher average kinetic energy, sample A must have the higher temperature. |
|
Will these magnets attract or repel each other? | [
"repel",
"attract"
] | 1 | Two magnets are placed as shown. | closed choice | grade4 | natural science | physics | Magnets | Identify magnets that attract or repel | Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart.
Whether a magnet attracts or repels other magnets depends on the positions of its poles, or ends. Every magnet has two poles: north and south.
Here are some examples of magnets. The north pole of each magnet is labeled N, and the south pole is labeled S.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel.
| To predict if these magnets will attract or repel, look at which poles are closest to each other.
The north pole of one magnet is closest to the south pole of the other magnet. Opposite poles attract. So, these magnets will attract each other. |
|
Will these magnets attract or repel each other? | [
"repel",
"attract"
] | 0 | Two magnets are placed as shown. | closed choice | grade5 | natural science | physics | Magnets | Identify magnets that attract or repel | Magnets can pull or push on other magnets without touching them. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes are called magnetic forces.
Magnetic forces are strongest at the magnets' poles, or ends. Every magnet has two poles: a north pole (N) and a south pole (S).
Here are some examples of magnets. Their poles are shown in different colors and labeled.
Whether a magnet attracts or repels other magnets depends on the positions of its poles.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel. | To predict if these magnets will attract or repel, look at which poles are closest to each other.
The south pole of one magnet is closest to the south pole of the other magnet. Like poles repel. So, these magnets will repel each other. |
|
What can Perry and Antonio trade to each get what they want? | [
"Antonio can trade his almonds for Perry's tomatoes.",
"Perry can trade his tomatoes for Antonio's sandwich.",
"Perry can trade his tomatoes for Antonio's broccoli.",
"Antonio can trade his broccoli for Perry's oranges."
] | 2 | Trade happens when people agree to exchange goods and services. People give up something to get something else. Sometimes people barter, or directly exchange one good or service for another.
Perry and Antonio open their lunch boxes in the school cafeteria. Both of them could be happier with their lunches. Perry wanted broccoli in his lunch and Antonio was hoping for tomatoes. Look at the images of their lunches. Then answer the question below. | closed choice | grade6 | social science | economics | Basic economic principles | Trade and specialization | Perry wanted broccoli in his lunch and Antonio was hoping for tomatoes. Look at the labeled part of the images.
Perry has tomatoes. Antonio has broccoli. They can trade tomatoes for broccoli to both be happier. Trading other things would not help either person get more items they want. |
||
Is the following statement about our solar system true or false?
Earth is the largest planet that is made mainly of rock. | [
"true",
"false"
] | 0 | Use the data to answer the question below. | true-or false | grade8 | natural science | earth-science | Astronomy | Analyze data to compare properties of planets | A planet's volume tells you the size of the planet.
The primary composition of a planet is what the planet is made mainly of. In our solar system, planets are made mainly of rock, gas, or ice.
The volume of a planet is a very large quantity. Large quantities such as this are often written in scientific notation.
For example, the volume of Jupiter is 1,430,000,000,000,000 km^3. In scientific notation, Jupiter's volume is written as 1.43 x 10^15 km^3.
To compare two numbers written in scientific notation, compare their exponents. The bigger the exponent is, the bigger the number is. For example:
1.43 x 10^15 is larger than 1.43 x 10^12
If their exponents are equal, compare the first numbers. For example:
1.43 x 10^15 is larger than 1.25 x 10^15
| The table tells you that Mercury, Venus, Earth, and Mars are the planets made mainly of rock. Of these planets, Earth has the volume with the largest exponent. So, Earth is the largest planet that is made mainly of rock. |
|
Look at the models of molecules below. Select the elementary substance. | [
"ethane",
"carbon tetraiodide",
"oxygen"
] | 2 | closed choice | grade6 | natural science | chemistry | Atoms and molecules | Identify elementary substances and compounds using models | There are more than 100 different chemical elements, or types of atoms. Chemical elements make up all of the substances around you.
A substance may be composed of one chemical element or multiple chemical elements. Substances that are composed of only one chemical element are elementary substances. Substances that are composed of multiple chemical elements bonded together are compounds.
Every chemical element is represented by its own atomic symbol. An atomic symbol may consist of one capital letter, or it may consist of a capital letter followed by a lowercase letter. For example, the atomic symbol for the chemical element boron is B, and the atomic symbol for the chemical element chlorine is Cl.
Scientists use different types of models to represent substances whose atoms are bonded in different ways. One type of model is a ball-and-stick model. The ball-and-stick model below represents a molecule of the compound boron trichloride.
In a ball-and-stick model, the balls represent atoms, and the sticks represent bonds. Notice that the balls in the model above are not all the same color. Each color represents a different chemical element. The legend shows the color and the atomic symbol for each chemical element in the substance. | |||
Not supported with pagination yet | Which figure of speech is used in this text?
The baby moon, a canoe, a silver papoose canoe, sails and sails in the Indian west.
—Carl Sandburg, "Early Moon" | [
"anaphora",
"assonance"
] | 1 | closed choice | grade11 | language science | figurative-language | Literary devices | Classify the figure of speech: review | Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive.
Anaphora is the repetition of the same word or words at the beginning of several phrases or clauses.
We are united. We are powerful. We are winners.
Antithesis involves contrasting opposing ideas within a parallel grammatical structure.
I want to help, not to hurt.
Apostrophe is a direct address to an absent person or a nonhuman entity.
Oh, little bird, what makes you sing so beautifully?
Assonance is the repetition of a vowel sound in a series of nearby words.
Try to light the fire.
Chiasmus is an expression in which the second half parallels the first but reverses the order of words.
Never let a fool kiss you or a kiss fool you.
A euphemism is a polite or indirect expression that is used to de-emphasize an unpleasant topic.
The head of Human Resources would never refer to firing people, only to laying them off.
Hyperbole is an obvious exaggeration that is not meant to be taken literally.
I ate so much that I think I might explode!
An oxymoron is a joining of two seemingly contradictory terms.
Some reviewers are calling this book a new classic.
A paradox is a statement that might at first appear to be contradictory, but that may in fact contain some truth.
Always expect the unexpected.
Understatement involves deliberately representing something as less serious or important than it really is.
As you know, it can get a little cold in the Antarctic. | The text uses assonance, the repetition of a vowel sound in a series of nearby words.
The words moon, canoe, and papoose share a vowel sound. |
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Not supported with pagination yet | Is the following trait inherited or acquired?
Ben has a scar on his left leg. | [
"acquired",
"inherited"
] | 0 | closed choice | grade5 | natural science | biology | Traits and heredity | Identify inherited and acquired traits | Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways.
Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned.
Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Children do not inherit their parents' acquired traits. | Children do not inherit their parent's scars. Instead, scars are caused by the environment. People can get scars after they get hurt. So, having a scar is an acquired trait. |
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Not supported with pagination yet | What information supports the conclusion that Maureen acquired this trait? | [
"Maureen learned how to play the cello in music class.",
"Maureen and her father play the cello together.",
"Maureen knows how to polish her cello."
] | 0 | Read the description of a trait.
Maureen can play the cello. | closed choice | grade7 | natural science | biology | Genes to traits | Inherited and acquired traits: use evidence to support a statement | Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways.
Inherited traits are passed down from biological parents to their offspring through genes. Genes are pieces of hereditary material that contain the instructions that affect inherited traits. Offspring receive their genes, and therefore gain their inherited traits, from their biological parents. Inherited traits do not need to be learned.
Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Parents do not pass acquired traits down to their offspring. | |
Think about the magnetic force between the magnets in each pair. Which of the following statements is true? | [
"The magnitude of the magnetic force is greater in Pair 2.",
"The magnitude of the magnetic force is the same in both pairs.",
"The magnitude of the magnetic force is greater in Pair 1."
] | 2 | The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material. | closed choice | grade8 | natural science | physics | Velocity, acceleration, and forces | Compare magnitudes of magnetic forces | Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces.
The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other.
You can change the magnitude of a magnetic force between two magnets by changing the distance between them. The magnitude of the magnetic force is greater when there is a smaller distance between the magnets. | The magnets in Pair 2 attract. The magnets in Pair 1 repel. But whether the magnets attract or repel affects only the direction of the magnetic force. It does not affect the magnitude of the magnetic force.
Distance affects the magnitude of the magnetic force. When there is a smaller distance between magnets, the magnitude of the magnetic force between them is greater.
There is a smaller distance between the magnets in Pair 1 than in Pair 2. So, the magnitude of the magnetic force is greater in Pair 1 than in Pair 2. |
|
Not supported with pagination yet | Is the following trait inherited or acquired?
Jacob can ride a motorcycle. | [
"acquired",
"inherited"
] | 0 | closed choice | grade5 | natural science | biology | Traits and heredity | Identify inherited and acquired traits | People are not born knowing how to ride a motorcycle. Instead, many people learn how to ride. So, riding a motorcycle is an acquired trait. |
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Not supported with pagination yet | Which text uses the word disinterested in its traditional sense? | [
"Liz is happy with her position as class treasurer. Though she would have the support of the student council, she is disinterested in running for student body president.",
"Liz is excellent in her position as class treasurer. She always manages to be disinterested in student council debates about the allocation of extracurricular funds."
] | 1 | closed choice | grade12 | language science | writing-strategies | Word usage and nuance | Explore words with new or contested usages | Words change in meaning when speakers begin using them in new ways. For example, the word peruse once only meant to examine in detail, but it's now also commonly used to mean to look through in a casual manner.
When a word changes in meaning, its correct usage is often debated. Although a newer sense of the word may be more commonly used, many people consider a word's traditional definition to be the correct usage. Being able to distinguish the different uses of a word can help you use it appropriately for different audiences.
Britney perused her notes, carefully preparing for her exam.
The traditional usage above is considered more standard.
David perused the magazine, absentmindedly flipping through the pages.
The nontraditional usage above is now commonly used, but traditional style guides generally advise against it. | The first text uses disinterested in its traditional sense: unbiased or impartial.
Liz is excellent in her position as class treasurer. She always manages to be disinterested in student council debates about the allocation of extracurricular funds.
The second text uses disinterested in its nontraditional sense: uninterested or indifferent.
Liz is happy with her position as class treasurer. Though she would have the support of the student council, she is disinterested in running for student body president.
Most style guides recommend to use the traditional sense of the word disinterested because it is considered more standard. |
|
Will these magnets attract or repel each other? | [
"attract",
"repel"
] | 0 | Two magnets are placed as shown. | closed choice | grade4 | natural science | physics | Magnets | Identify magnets that attract or repel | Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart.
Whether a magnet attracts or repels other magnets depends on the positions of its poles, or ends. Every magnet has two poles: north and south.
Here are some examples of magnets. The north pole of each magnet is labeled N, and the south pole is labeled S.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel.
| To predict if these magnets will attract or repel, look at which poles are closest to each other.
The south pole of one magnet is closest to the north pole of the other magnet. Opposite poles attract. So, these magnets will attract each other. |
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Not supported with pagination yet | What does the euphemism in this text suggest?
Jackson is big-boned, so despite being in middle school, he often shops in the men's department. | [
"Jackson is overweight.",
"Jackson is tall for his age."
] | 0 | closed choice | grade11 | language science | figurative-language | Literary devices | Interpret the figure of speech | Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive.
A euphemism is a polite or indirect expression that is used to de-emphasize an unpleasant topic.
The head of Human Resources would never refer to firing people, only to laying them off. | The text uses a euphemism, a polite or indirect expression that is used to de-emphasize an unpleasant topic.
The euphemism big-boned suggests that Jackson is overweight. |
|
Will these magnets attract or repel each other? | [
"repel",
"attract"
] | 0 | Two magnets are placed as shown. | closed choice | grade5 | natural science | physics | Magnets | Identify magnets that attract or repel | Magnets can pull or push on other magnets without touching them. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes are called magnetic forces.
Magnetic forces are strongest at the magnets' poles, or ends. Every magnet has two poles: a north pole (N) and a south pole (S).
Here are some examples of magnets. Their poles are shown in different colors and labeled.
Whether a magnet attracts or repels other magnets depends on the positions of its poles.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel. | To predict if these magnets will attract or repel, look at which poles are closest to each other.
The south pole of one magnet is closest to the south pole of the other magnet. Like poles repel. So, these magnets will repel each other. |
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Not supported with pagination yet | What information supports the conclusion that Tanvi inherited this trait? | [
"When she was younger, Tanvi wore ribbons in her naturally black hair.",
"Some people use a hair dryer to straighten their hair. But Tanvi and her brothers have naturally straight hair.",
"Both of Tanvi's biological parents have naturally black hair."
] | 2 | Read the description of a trait.
Tanvi has naturally black hair. | closed choice | grade7 | natural science | biology | Genes to traits | Inherited and acquired traits: use evidence to support a statement | Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways.
Inherited traits are passed down from biological parents to their offspring through genes. Genes are pieces of hereditary material that contain the instructions that affect inherited traits. Offspring receive their genes, and therefore gain their inherited traits, from their biological parents. Inherited traits do not need to be learned.
Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Parents do not pass acquired traits down to their offspring. | |
Not supported with pagination yet | What is the mass of a goat? | [
"70 tons",
"70 ounces",
"70 pounds"
] | 2 | Select the best estimate. | closed choice | grade4 | natural science | units-and-measurement | Units and measurement | Choose customary units of mass | Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means.
Mass is a measurement of how much matter something contains.
There are many different units of mass. When you are using customary units, mass may be written with units of ounces, pounds, or tons.
There are 16 ounces in 1 pound and 2,000 pounds in 1 ton.
So, 1 ounce is less than 1 pound and much less than 1 ton.
A slice of bread has a mass of about 1 ounce, while a can of beans has a mass of about 1 pound. A small car has a mass of about 1 ton. | The best estimate for the mass of a goat is 70 pounds.
70 ounces is too light and 70 tons is too heavy. |
What is the capital of Oklahoma? | [
"Little Rock",
"Tulsa",
"Oklahoma City",
"Trenton"
] | 2 | closed choice | grade5 | social science | geography | State capitals | Identify state capitals of the Southeast | Oklahoma City is the capital of Oklahoma. |
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Not supported with pagination yet | What does the idiom in this text suggest?
If you don't mind waking up at the crack of dawn (or if you even prefer it), consider a career as a baker, a teacher, or an investment banker. | [
"You have to wake up at sunset.",
"You have to wake up very early."
] | 1 | closed choice | grade10 | language science | figurative-language | Literary devices | Interpret figures of speech | Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive.
An idiom is an expression that cannot be understood literally. Its meaning must be learned.
The assignment was a piece of cake. | The text uses an idiom, an expression that cannot be understood literally.
The idiom at the crack of dawn suggests that you have to wake up very early. Dawn is the beginning of the day, so the idiom means very early. |
|
Identify the question that Julia and Andy's experiment can best answer. | [
"Does Julia's snowboard slide down a hill in less time when it has a layer of wax or when it does not have a layer of wax?",
"Does Julia's snowboard slide down a hill in less time when it has a thin layer of wax or a thick layer of wax?"
] | 0 | The passage below describes an experiment. Read the passage and then follow the instructions below.
Julia applied a thin layer of wax to the underside of her snowboard and rode the board straight down a hill. Then, she removed the wax and rode the snowboard straight down the hill again. She repeated the rides four more times, alternating whether she rode with a thin layer of wax on the board or not. Her friend Andy timed each ride. Julia and Andy calculated the average time it took to slide straight down the hill on the snowboard with wax compared to the average time on the snowboard without wax.
Figure: snowboarding down a hill. | closed choice | grade6 | natural science | science-and-engineering-practices | Designing experiments | Identify the experimental question | Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment.
Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured.
First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested.
Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured.
Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height.
Examples of questions that this experiment can answer include:
Does soil type affect the height of daffodil plants?
Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil?
Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil? | ||
Not supported with pagination yet | Which word would you find on a dictionary page with the following guide words?
octopus - owl | [
"ox",
"orbit"
] | 1 | closed choice | grade3 | language science | reference-skills | Reference skills | Use guide words | Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order.
To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on.
If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed. | Put the words in alphabetical order.
Since orbit is between the guide words octopus - owl, it would be found on that page. |
|
What is the name of the colony shown? | [
"West Virginia",
"Virginia",
"Delaware",
"North Carolina"
] | 1 | closed choice | grade4 | social science | us-history | English colonies in North America | Identify the Thirteen Colonies | The colony is Virginia.
The Virginia Colony included land that would later become part of the state of West Virginia. West Virginia was never its own colony. |
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Not supported with pagination yet | What does the verbal irony in this text suggest?
"Sleeping through the rooster's crowing was no problem," Chandler joked with a yawn. | [
"Chandler slept poorly.",
"Chandler slept well."
] | 0 | closed choice | grade8 | language science | figurative-language | Literary devices | Interpret figures of speech | Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive.
Verbal irony involves saying one thing but implying something very different. People often use verbal irony when they are being sarcastic.
Olivia seems thrilled that her car keeps breaking down.
Each breakdown is as enjoyable as a punch to the face. | The text uses verbal irony, which involves saying one thing but implying something very different.
Sleeping through the rooster's crowing was no problem ironically suggests that Chandler slept poorly. Chandler was tired, so the rooster's crowing was clearly a problem. |
|
Identify the question that Shawn's experiment can best answer. | [
"Do bananas develop more brown spots when they are kept at room temperature compared to in a cold refrigerator?",
"Do bananas develop more brown spots if they are kept in bags with holes compared to bags without holes?"
] | 1 | The passage below describes an experiment. Read the passage and then follow the instructions below.
Shawn divided 40 evenly among eight paper bags and sealed the bags. He poked 20 small holes in four of the bags and left the other four without holes. He kept the bags at room temperature for three days. Then, Shawn opened the bags and counted the number of brown spots on each banana. He compared the average number of brown spots on bananas from bags with holes to the average number of brown spots on bananas from bags without holes.
Figure: unripe bananas. | closed choice | grade6 | natural science | science-and-engineering-practices | Designing experiments | Identify the experimental question | Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment.
Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured.
First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested.
Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured.
Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height.
Examples of questions that this experiment can answer include:
Does soil type affect the height of daffodil plants?
Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil?
Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil? | ||
Not supported with pagination yet | Select the animal that has a backbone. | [
"dog",
"curlyhair tarantula"
] | 0 | Hint: Mammals, birds, fish, reptiles, and amphibians all have backbones. | closed choice | grade2 | natural science | biology | Classification | Identify animals with and without backbones | Some animals have a backbone. The backbone is made of many bones in an animal's back. An animal's backbone helps connect the different parts of its body. In the drawings below, each animal's backbone is colored orange.
Other animals do not have a backbone. In fact, these animals don't have any bones! Some animals without backbones have a hard outer cover. Other animals have a soft body. | A dog is a mammal. Like other mammals, a dog has a backbone.
Like other tarantulas, a curlyhair tarantula does not have a backbone. It has a hard outer cover. |
Complete the sentence.
The mutation in the () affected the structure and function of the (). | [
"ULTRAPETALA1 protein . . . ULT1 gene",
"ULT1 gene . . . ULTRAPETALA1 protein"
] | 1 | The following passage describes the effects of a gene mutation, which is a permanent change in a gene. Read the passage and then follow the instructions below.
Some plant proteins control how flowers grow and develop. In Arabidopsis thaliana (A. thaliana) plants, one of these proteins is called ULTRAPETALA1. The ULTRAPETALA1 protein is encoded by the ULT1 gene.
The ULTRAPETALA1 protein allows only a specific number of cells in the growing flower bud to divide and form petals. This results in A. thaliana flowers with four petals.
A certain A. thaliana plant had a mutation in the ULT1 gene that caused the plant to have flowers with six petals instead of four. Compared to the ULT1 gene without a mutation, the mutated ULT1 gene encoded a form of the ULTRAPETALA1 protein with a different structure.
This different form of the ULTRAPETALA1 protein allowed more cells than normal to grow and form petals.
Figure: an A. thaliana flower with four petals. | closed choice | grade6 | natural science | biology | Genes to traits | Describe the effects of gene mutations on organisms | An organism's genes contain information about its proteins. Each gene encodes, or contains the instructions for making, one protein or a group of proteins.
A permanent change in a gene is called a mutation. Because a mutation changes a gene, the mutation may change the structure of the protein encoded by that gene.
The function of a protein depends on its structure. So, if a mutation in a gene changes a protein's structure, the mutation may also change the protein's function.
An organism's observable traits are affected by the functions of its proteins. So, a gene mutation that affects a protein's function may also affect an organism's observable traits. | A mutation in a gene may affect the protein it encodes.
So, the mutation in the ULT1 gene affected the structure and function of the ULTRAPETALA1 protein. |
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Not supported with pagination yet | Complete the statement.
Neon is (). | [
"a compound",
"an elementary substance"
] | 1 | Neon is a gas that is used to make glowing electric lights and signs. The chemical formula for neon is Ne. | closed choice | grade5 | natural science | chemistry | Atoms and molecules | Classify elementary substances and compounds using chemical formulas | Every substance around you is made of one or more chemical elements, or types of atoms. Substances that are made of only one chemical element are elementary substances. Substances that are made of two or more chemical elements bonded together are compounds.
Every chemical element is represented by its own symbol. For some elements, the symbol is one capital letter. For other elements, the symbol is one capital letter and one lowercase letter. For example, the symbol for the element fluorine is F, and the symbol for the element beryllium is Be.
The symbol for each element in a substance is shown in the substance's chemical formula.
An elementary substance is represented by a chemical formula that contains only one symbol.
The symbol may be followed by a subscript. A subscript is text that is smaller and placed lower than the normal line of text. A subscript is included when the atoms in the elementary substance are bonded to form molecules. The subscript tells you the number of atoms in each molecule.
For example, the chemical formula for the elementary substance oxygen is O2. The formula has a subscript of 2. This subscript tells you that there are two atoms in the molecule represented by this chemical formula.
The chemical element represented by the symbol O is also called oxygen. So, the formula O2 tells you that each molecule of O2 contains two oxygen atoms.
A compound is represented by a chemical formula that contains multiple symbols.
For example, in the compound beryllium fluoride, there is one beryllium atom for every two fluorine atoms. This combination is shown in the compound's chemical formula, BeF2. In the formula, the symbol Be represents one beryllium atom. The symbol F followed by the subscript 2 represents two fluorine atoms. | You can tell whether neon is an elementary substance or a compound by counting the number of symbols in its chemical formula. A symbol contains either one capital letter or a capital letter followed by one or two lowercase letters.
The chemical formula for neon is Ne. This formula contains one symbol: Ne. So, the formula tells you that neon is made of one chemical element.
Substances made of only one chemical element are elementary substances. So, neon is an elementary substance. |
Which month has the lowest average temperature in Amsterdam? | [
"January",
"February",
"November"
] | 1 | Use the graph to answer the question below. | closed choice | grade4 | natural science | earth-science | Weather and climate | Use climate data to make predictions | Scientists record climate data from places around the world. Temperature is one type of climate data. Scientists collect data over many years. They can use this data to calculate the average temperature for each month. The average temperature can be used to describe the climate of a location.
A line graph can be used to show the average temperature each month. Months with higher dots on the graph have higher average temperatures. | To describe the average temperature trends in Amsterdam, look at the graph.
Choice "Feb" is incorrect.
Choice "Nov" is incorrect.
Choice "Jan" is incorrect.
The average temperature in February is around 2°C. This is the lowest average temperature of all of the months. |
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Not supported with pagination yet | Which object has the least thermal energy? | [
"a 220-gram bottle of water at a temperature of 54°F",
"a 220-gram bottle of water at a temperature of 50°F",
"a 220-gram bottle of water at a temperature of 73°F"
] | 1 | The objects are identical except for their temperatures. | closed choice | grade4 | natural science | physics | Heat and thermal energy | How is temperature related to thermal energy? | All solids, liquids, and gases are made of matter. Matter is made up of tiny particles that are always moving. The energy from the motion of these particles is called thermal energy.
Temperature measures how hot or cold matter is. If the particles in matter slow down, the temperature goes down. The matter now has both less thermal energy and a lower temperature. | All three bottles of water have the same mass but different temperatures. Since the 50°F bottle of water is the coldest, it has the least thermal energy. |
Which of the following was an independent variable in this experiment? | [
"the number of days until a seed germinated",
"the temperature of the heating pad"
] | 1 | The passage below describes an experiment. Read the passage and think about the variables that are described.
Pablo wanted to grow cucumbers from seeds. He read that using a heating pad to heat up potting soil could help make seeds germinate, or sprout, faster. Pablo wondered whether the temperature of the heating pad would affect how quickly the seeds germinated.
Pablo prepared two potting trays, each made up of ten small pots of soil. He planted one cucumber seed in each small pot and arranged the potting trays near a sunny window. He set an electric heating pad to 75°F and placed it under one potting tray. He set a second heating pad to 85°F and placed it under the other potting tray. Pablo observed the pots daily, and he counted the number of days it took until a seed germinated in each pot.
Hint: An independent variable is a variable whose effect you are investigating. A dependent variable is a variable that you measure.
Figure: germinating plants in a potting tray. | closed choice | grade6 | natural science | science-and-engineering-practices | Designing experiments | Identify independent and dependent variables | Experiments have variables, or parts that change. You can design an experiment to find out how one variable affects another variable. For example, imagine that you want to find out if fertilizer affects the number of tomatoes a tomato plant grows. To answer this question, you decide to set up two equal groups of tomato plants. Then, you add fertilizer to the soil of the plants in one group but not in the other group. Later, you measure the effect of the fertilizer by counting the number of tomatoes on each plant.
In this experiment, the amount of fertilizer added to the soil and the number of tomatoes were both variables.
The amount of fertilizer added to the soil was an independent variable because it was the variable whose effect you were investigating. This type of variable is called independent because its value does not depend on what happens after the experiment begins. Instead, you decided to give fertilizer to some plants and not to others.
The number of tomatoes was a dependent variable because it was the variable you were measuring. This type of variable is called dependent because its value can depend on what happens in the experiment. | ||
Think about the magnetic force between the magnets in each pair. Which of the following statements is true? | [
"The magnetic force is stronger in Pair 1.",
"The strength of the magnetic force is the same in both pairs.",
"The magnetic force is stronger in Pair 2."
] | 1 | The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material. | closed choice | grade4 | natural science | physics | Magnets | Compare strengths of magnetic forces | Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart.
These pulls and pushes between magnets are called magnetic forces. The stronger the magnetic force between two magnets, the more strongly the magnets attract or repel each other. | Distance affects the strength of the magnetic force. But the distance between the magnets in Pair 1 and in Pair 2 is the same.
So, the strength of the magnetic force is the same in both pairs. |
|
Not supported with pagination yet | Which is a sentence fragment? | [
"The girls climb on the bars at the playground.",
"Loves to learn about reptiles, like turtles and snakes."
] | 1 | closed choice | grade3 | language science | writing-strategies | Sentences, fragments, and run-ons | Is it a complete sentence, a fragment, or a run-on? | A sentence is a group of words that forms a complete thought. It has both a subject and a verb.
My friends walk along the path.
A sentence fragment is a group of words that does not express a complete thought. It is usually missing a subject or a verb.
Knows the answer.
This is a sentence fragment. It is missing a subject.
Who knows the answer? She knows the answer.
The bright red car.
This is a sentence fragment. It is missing a verb.
What did the bright red car do? The bright red car stopped.
A run-on sentence is made up of two sentences that are joined without end punctuation or with just a comma.
I knocked on the door it opened.
It started raining, we ran inside.
To fix a run-on sentence, separate it into two sentences. Add end punctuation after the first sentence, and capitalize the second sentence.
I knocked on the door. It opened.
It started raining. We ran inside.
You can also fix a run-on sentence by rewriting it as a compound sentence. A compound sentence is two sentences joined by a comma and a conjunction such as and, but, or, or so.
I knocked on the door, and it opened.
It started raining, so we ran inside. | Loves to learn about reptiles, like turtles and snakes is a sentence fragment. It is missing a subject. |
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Not supported with pagination yet | Which word would you find on a dictionary page with the following guide words?
cabinet - cot | [
"creek",
"cheese"
] | 1 | closed choice | grade3 | language science | reference-skills | Reference skills | Use guide words | Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order.
To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on.
If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed. | Put the words in alphabetical order.
Since cheese is between the guide words cabinet - cot, it would be found on that page. |
|
Not supported with pagination yet | Select the animal that has a backbone. | [
"black widow spider",
"sheep"
] | 1 | Hint: Mammals, birds, fish, reptiles, and amphibians all have backbones. | closed choice | grade2 | natural science | biology | Classification | Identify animals with and without backbones | Some animals have a backbone. The backbone is made of many bones in an animal's back. An animal's backbone helps connect the different parts of its body. In the drawings below, each animal's backbone is colored orange.
Other animals do not have a backbone. In fact, these animals don't have any bones! Some animals without backbones have a hard outer cover. Other animals have a soft body. | Like other spiders, a black widow spider does not have a backbone. It has a hard outer cover.
A sheep is a mammal. Like other mammals, a sheep has a backbone. |
Which animal's limbs are also adapted for swimming? | [
"nilgai",
"California sea lion"
] | 1 | Humpback whales are found in the world's oceans. They live underwater, but come to the surface to breathe air.
The has flippers for limbs. Its limbs are adapted for swimming.
Figure: humpback whale. | closed choice | grade4 | natural science | biology | Adaptations | Animal adaptations: feet and limbs | An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
Arms, legs, flippers, and wings are different types of limbs. The type of limbs an animal has is an example of an adaptation. Animals' limbs can be adapted in different ways. For example, long legs might help an animal run fast. Flippers might help an animal swim. Wings might help an animal fly. | Look at the picture of the humpback whale.
The humpback whale uses its flippers to help push itself through water. The flippers can also help it change direction while swimming.
Now look at each animal. Figure out which animal has a similar adaptation.
The California sea lion has flippers. Its limbs are adapted for swimming.
The nilgai has long legs. Its limbs are not adapted for swimming. The nilgai uses its limbs to walk and run on land. |
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Not supported with pagination yet | What does the idiom in this text suggest?
Reagan has a lot on her plate: she is attending college, has a full-time job as a waitress, and volunteers at the animal shelter. | [
"Reagan has no time to eat well.",
"Reagan has many responsibilities."
] | 1 | closed choice | grade9 | language science | figurative-language | Literary devices | Interpret figures of speech | Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive.
An idiom is an expression that cannot be understood literally. Its meaning must be learned.
The assignment was a piece of cake. | The text uses an idiom, an expression that cannot be understood literally.
The idiom a lot on her plate suggests that Reagan has many responsibilities. If you have a lot on your plate, you are busy with many different obligations. |
|
Think about the magnetic force between the magnets in each pair. Which of the following statements is true? | [
"The magnitude of the magnetic force is greater in Pair 2.",
"The magnitude of the magnetic force is greater in Pair 1.",
"The magnitude of the magnetic force is the same in both pairs."
] | 0 | The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material. | closed choice | grade6 | natural science | physics | Velocity, acceleration, and forces | Compare magnitudes of magnetic forces | Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces.
The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other.
You can change the magnitude of a magnetic force between two magnets by changing the distance between them. The magnitude of the magnetic force is greater when there is a smaller distance between the magnets. | Distance affects the magnitude of the magnetic force. When there is a smaller distance between magnets, the magnitude of the magnetic force between them is greater.
There is a smaller distance between the magnets in Pair 2 than in Pair 1. So, the magnitude of the magnetic force is greater in Pair 2 than in Pair 1. |
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Which solution has a higher concentration of pink particles? | [
"neither; their concentrations are the same",
"Solution B",
"Solution A"
] | 2 | The diagram below is a model of two solutions. Each pink ball represents one particle of solute. | closed choice | grade6 | natural science | chemistry | Solutions | Compare concentrations of solutions | A solution is made up of two or more substances that are completely mixed. In a solution, solute particles are mixed into a solvent. The solute cannot be separated from the solvent by a filter. For example, if you stir a spoonful of salt into a cup of water, the salt will mix into the water to make a saltwater solution. In this case, the salt is the solute. The water is the solvent.
The concentration of a solute in a solution is a measure of the ratio of solute to solvent. Concentration can be described in terms of particles of solute per volume of solvent.
concentration = particles of solute / volume of solvent | In Solution A and Solution B, the pink particles represent the solute. To figure out which solution has a higher concentration of pink particles, look at both the number of pink particles and the volume of the solvent in each container.
Use the concentration formula to find the number of pink particles per milliliter.
Solution A has more pink particles per milliliter. So, Solution A has a higher concentration of pink particles. |
|
Which bird's beak is also adapted to crack hard seeds? | [
"indigo bunting",
"Asian openbill"
] | 0 | Evening grosbeaks eat small, hard seeds. The shape of the 's beak is adapted to crack open small, hard seeds.
Figure: evening grosbeak. | closed choice | grade5 | natural science | biology | Adaptations | Animal adaptations: beaks, mouths, and necks | An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The shape of a bird's beak is one example of an adaptation. Birds' beaks can be adapted in different ways. For example, a sharp hooked beak might help a bird tear through meat easily. A short, thick beak might help a bird break through a seed's hard shell. Birds that eat similar food often have similar beaks. | Look at the picture of the evening grosbeak.
The evening grosbeak has a short, thick beak. Its beak is adapted to crack hard seeds. The evening grosbeak uses its short, thick beak to press down on a seed and crack open its hard shell.
Now look at each bird. Figure out which bird has a similar adaptation.
The indigo bunting has a short, thick beak. Its beak is adapted to crack hard seeds.
The Asian openbill has a long beak with a gap in the middle. Its beak is not adapted to crack hard seeds. The Asian openbill uses its beak to eat snails. |
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Not supported with pagination yet | What does the idiom in this text suggest?
In such an unfamiliar environment, Xavier was a fish out of water. | [
"Xavier didn't have any friends.",
"Xavier felt out of place."
] | 1 | closed choice | grade10 | language science | figurative-language | Literary devices | Interpret figures of speech | Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive.
An idiom is an expression that cannot be understood literally. Its meaning must be learned.
The assignment was a piece of cake. | The text uses an idiom, an expression that cannot be understood literally.
The idiom a fish out of water suggests that Xavier felt out of place. A fish out of water is someone out of his or her usual, comfortable environment. |
|
What is the capital of Pennsylvania? | [
"Pittsburgh",
"Philadelphia",
"Harrisburg",
"Montpelier"
] | 2 | closed choice | grade4 | social science | geography | State capitals | Identify state capitals of the Northeast | Harrisburg is the capital of Pennsylvania. |
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Which part of the watermelon plant makes the seeds? | [
"the fruit",
"the flowers"
] | 1 | A watermelon plant can grow seeds. | closed choice | grade4 | natural science | biology | Plants | Describe and construct flowering plant life cycles | Many plants have flowers. These plants can use their flowers to reproduce, or make new plants like themselves. How do plants use their flowers to reproduce?
First, the male part of the flower makes pollen, and the female part makes eggs. Animals, wind, or water can move pollen. Pollination is what happens when pollen is moved to the female part of the flower.
After pollination, sperm from the pollen can combine with the eggs. This is called fertilization. The fertilized eggs grow into seeds. The fruit grows around the seeds. Later, a seed can fall out of the fruit. It can germinate, or start to grow into a new plant. | Flowers make seeds. After a flower is pollinated, male cells from the pollen combine with eggs. This is called fertilization. The fertilized eggs grow into seeds.
The fruit can grow around the seeds. But the fruit does not make seeds. Both the fruit and the seeds grow from parts of the flower. |
|
What is the capital of Maryland? | [
"Jefferson City",
"Albany",
"Annapolis",
"Dover"
] | 2 | closed choice | grade4 | social science | geography | State capitals | Identify state capitals of the Northeast | Annapolis is the capital of Maryland. |
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Not supported with pagination yet | Which figure of speech is used in this text?
With malice toward none, with charity for all, with firmness in the right as God gives us to see the right, let us strive on to finish the work we are in.
—President Abraham Lincoln, second inaugural address | [
"apostrophe",
"anaphora"
] | 1 | closed choice | grade11 | language science | figurative-language | Literary devices | Classify the figure of speech: anaphora, antithesis, apostrophe, assonance, chiasmus, understatement | Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive.
Anaphora is the repetition of the same word or words at the beginning of several phrases or clauses.
We are united. We are powerful. We are winners.
Antithesis involves contrasting opposing ideas within a parallel grammatical structure.
I want to help, not to hurt.
Apostrophe is a direct address to an absent person or a nonhuman entity.
Oh, little bird, what makes you sing so beautifully?
Assonance is the repetition of a vowel sound in a series of nearby words.
Try to light the fire.
Chiasmus is an expression in which the second half parallels the first but reverses the order of words.
Never let a fool kiss you or a kiss fool you.
Understatement involves deliberately representing something as less serious or important than it really is.
As you know, it can get a little cold in the Antarctic. | The text uses anaphora, the repetition of the same word or words at the beginning of several phrases or clauses.
Lincoln repeats the word with at the beginning of each phrase. |
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Not supported with pagination yet | Assume all other forces on Madelyn are balanced. Which statement describes the forces on Madelyn? | [
"The forces are unbalanced, so there is a net force on Madelyn.",
"The forces are balanced, so there is no net force on Madelyn."
] | 0 | Madelyn is sitting on a roller coaster cart as it reaches the bottom of a big loop. Earth's gravity is pulling down on Madelyn with a force of 600N. The seat of the cart is pushing up on Madelyn with a force of 1,200N. | closed choice | grade8 | natural science | physics | Velocity, acceleration, and forces | Balanced and unbalanced forces | A force is a push or a pull that acts on an object. Every force has a direction and a magnitude, or strength. If two forces act on an object in opposite directions, the forces are called opposing forces.
When opposing forces have the same magnitude, they are balanced. If all the forces on an object are balanced, there is no net force on the object.
When opposing forces have different magnitudes, the forces are unbalanced. If any forces on an object are unbalanced, there is a net force on the object. | To determine if there is a net force on Madelyn, look at the forces:
Earth's gravity is pulling Madelyn down with a force of 600 N.
The seat of the cart is pushing Madelyn up with a force of 1,200 N.
The forces are in opposite directions, and the forces have different magnitudes: 600 N and 1,200 N. This means that the forces are unbalanced, so there is a net force on Madelyn. |
Not supported with pagination yet | Which pot of spaghetti sauce has a lower temperature? | [
"the pot of spaghetti sauce with more thermal energy",
"the pot of spaghetti sauce with less thermal energy"
] | 1 | Two pots of spaghetti sauce are identical except for their thermal energies. | closed choice | grade5 | natural science | physics | Heat and thermal energy | How are temperature and mass related to thermal energy? | Matter is made of tiny particles called atoms. Atoms are always moving.
The energy of moving atoms is called thermal energy. The total amount of thermal energy in matter depends on three things: the type of matter, the amount of matter, and how fast the atoms are moving.
Temperature measures how hot or cold matter is. If the atoms in matter slow down, the temperature goes down. The matter now has both less thermal energy and a lower temperature.
What happens if the amount of matter changes? A 2-kilogram brick at 70°F has twice as much thermal energy as a 1-kilogram brick at 70°F. The two bricks have the same temperature, but the larger brick has twice as many atoms. So, it has twice as much thermal energy. | The two pots of spaghetti sauce are made of the same material and have the same mass. So, the pot of spaghetti sauce with less thermal energy has a lower temperature. |
Which of these states is farthest west? | [
"Massachusetts",
"South Dakota",
"South Carolina",
"Maine"
] | 1 | closed choice | grade4 | social science | geography | Maps | Read a map: cardinal directions | Maps have four cardinal directions, or main directions. Those directions are north, south, east, and west.
A compass rose is a set of arrows that point to the cardinal directions. A compass rose usually shows only the first letter of each cardinal direction.
The north arrow points to the North Pole. On most maps, north is at the top of the map. | To find the answer, look at the compass rose. Look at which way the west arrow is pointing. South Dakota is farthest west. |
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Not supported with pagination yet | Which word would you find on a dictionary page with the following guide words?
den - dream | [
"doing",
"dance"
] | 0 | closed choice | grade2 | language science | reference-skills | Reference skills | Use guide words | Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order.
To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. | Put the words in alphabetical order.
Since doing is between the guide words den - dream, it would be found on that page. |
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Not supported with pagination yet | Complete the sentence so that it uses personification.
"I can't believe I tripped," Darrell remarked. "The curb must have ()". | [
"jumped out in front of me",
"had an uneven surface"
] | 0 | closed choice | grade9 | language science | writing-strategies | Creative techniques | Use personification | Personification is giving human characteristics to nonhuman things. It is a figure of speech that can be used to make writing more interesting or to emphasize a point.
The trees danced in the wind.
The word danced describes the trees as if they were people. Unlike people, however, trees can't actually dance. Instead, the personification suggests that the trees are moving. | Complete the sentence with the phrase jumped out in front of me. It describes the curb as if it were a mischievous, unpredictable person. |
|
Complete the sentence.
The mutation in the () affected the structure and function of the (). | [
"GA 3-oxidase protein . . . LH gene",
"LH gene . . . GA 3-oxidase protein"
] | 1 | The following passage describes the effects of a gene mutation, which is a permanent change in a gene. Read the passage and then follow the instructions below.
A pea plant's height is affected by substances that are made inside the plant's cells. One of these substances is called gibberellin.
Gibberellin is made in a pea plant's cells by a protein called GA 3-oxidase. The GA 3-oxidase protein is encoded by the LH gene.
A certain pea plant had a mutation in its LH gene. Compared to the LH gene without a mutation, the mutated LH gene encoded a form of the GA 3-oxidase protein with a different structure.
This different form of the GA 3-oxidase protein could make only a small amount of gibberellin. The plant with the mutation grew to a shorter height than pea plants containing more gibberellin.
Figure: pea plants with different amounts of gibberellin. | closed choice | grade6 | natural science | biology | Genes to traits | Describe the effects of gene mutations on organisms | An organism's genes contain information about its proteins. Each gene encodes, or contains the instructions for making, one protein or a group of proteins.
A permanent change in a gene is called a mutation. Because a mutation changes a gene, the mutation may change the structure of the protein encoded by that gene.
The function of a protein depends on its structure. So, if a mutation in a gene changes a protein's structure, the mutation may also change the protein's function.
An organism's observable traits are affected by the functions of its proteins. So, a gene mutation that affects a protein's function may also affect an organism's observable traits. | A mutation in a gene may affect the protein it encodes.
So, the mutation in the LH gene affected the structure and function of the GA 3-oxidase protein. |
|
Think about the magnetic force between the magnets in each pair. Which of the following statements is true? | [
"The magnitude of the magnetic force is smaller in Pair 1.",
"The magnitude of the magnetic force is smaller in Pair 2.",
"The magnitude of the magnetic force is the same in both pairs."
] | 1 | The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different sizes. | closed choice | grade6 | natural science | physics | Velocity, acceleration, and forces | Compare magnitudes of magnetic forces | Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces.
The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other.
You can change the magnitude of a magnetic force between two magnets by using magnets of different sizes. The magnitude of the magnetic force is smaller when the magnets are smaller. | The magnets in Pair 2 attract. The magnets in Pair 1 repel. But whether the magnets attract or repel affects only the direction of the magnetic force. It does not affect the magnitude of the magnetic force.
Magnet sizes affect the magnitude of the magnetic force. Imagine magnets that are the same shape and made of the same material. The smaller the magnets, the smaller the magnitude of the magnetic force between them.
Magnet A is the same size in both pairs. But Magnet B is smaller in Pair 2 than in Pair 1. So, the magnitude of the magnetic force is smaller in Pair 2 than in Pair 1. |
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Not supported with pagination yet | What information supports the conclusion that Sandra acquired this trait? | [
"Sandra's scar was caused by an accident. She cut her arm when she fell off her bicycle.",
"Sandra's scar is on her right elbow. Her father also has a scar on his right elbow.",
"Sandra's sister has a bruise from falling on her elbow."
] | 0 | Read the description of a trait.
Sandra has a scar on her right elbow. | closed choice | grade8 | natural science | biology | Genes to traits | Inherited and acquired traits: use evidence to support a statement | Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways.
Inherited traits are passed down from biological parents to their offspring through genes. Genes are pieces of hereditary material that contain the instructions that affect inherited traits. Offspring receive their genes, and therefore gain their inherited traits, from their biological parents. Inherited traits do not need to be learned.
Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Parents do not pass acquired traits down to their offspring. | |
Complete the statement.
Hydrazine is (). | [
"an elementary substance",
"a compound"
] | 1 | The model below represents a molecule of hydrazine. Hydrazine is used in some types of rocket fuels. | closed choice | grade5 | natural science | chemistry | Atoms and molecules | Classify elementary substances and compounds using models | All substances are made of one or more chemical elements, or types of atoms. Substances that are made of only one chemical element are elementary substances. Substances that are made of two or more chemical elements bonded together are compounds.
Every chemical element is represented by its own symbol. For some elements, the symbol is one capital letter. For other elements, the symbol is one capital letter and one lowercase letter. For example, the symbol for the chemical element boron is B, and the symbol for the chemical element chlorine is Cl.
Scientists can use models to represent molecules. A ball-and-stick model of a molecule is shown below. This model represents a molecule of the compound boron trichloride.
In a ball-and-stick model, the balls represent atoms, and the sticks represent chemical bonds. Notice how each ball is labeled with a symbol for a chemical element. The ball represents one atom of that element. | Count the number of chemical elements represented in the model. Then, decide if hydrazine is an elementary substance or a compound.
In this model, each ball is labeled with N for nitrogen or H for hydrogen. So, the model shows you that hydrazine is made of two chemical elements bonded together.
Substances made of two or more chemical elements bonded together are compounds. So, hydrazine is a compound. |