original: String theory is a developing branch of theoretical physics that combines quantum mechanics and general relativity into a quantum theory of gravity.
simplifications: String theory develops theoretical physics it combines quantum mechanics and general relativity into a quantum theory of gravity. String theory in physics, combines quantum mechanics and relativity into a theory of gravity. String theory is a developing branch of theoretical physics. It combines quantum mechanics and general relativity into a quantum theory of gravity. String theory is a developing branch of theoretical physics. It combines quantum mechanics and general relativity into a quantum theory of gravity. String theory is a developing branch of theoretical physics. It combines quantum mechanics and general relativity into a quantum theory of gravity. String theory is a branch of physics that combines quantum mechanics and general relativity. String theory combines quantum mechanics and general relativity to become a quantum theory of gravity. String Theory is a growing branch of physics that adds quantum mechanics and general relativity into a quantum theory of gravity. A developing branch of theoretical physics is string theory. It combines quantum mechanics and general relativity into a quantum theory of gravity. String Theory is a creating branch of theoretical physics that combines quantum mechanics and relativity into quantum gravity theory.