question: People without safe drinking water may get an illness called dysentery. Dysentery is caused by a type of amoeba that lives inside the body. Doctors can find these amoebas by looking at body samples under a microscope. Which characteristic of amoebas best explains why doctors use microscopes to find dysentery amoebas?
choices.text: Amoebas can change their shape. Amoebas need humans to survive. Amoebas look just like human cells. Amoebas are made of only one cell.
choices.label: A B C D