sentence2_structure: objects<>are<>atomic/subatomic$$$The specialized study of the motion of objects<>is called<>quantum mechanics
sentence1: Quantum mechanics is the branch of mechanics that deals with the motion of electrons, protons, neutrons, and other subatomic particles that make  up atoms and molecules.
sentence2: The specialized study of the motion of objects that are atomic/subatomic in size is called quantum mechanics.
question: The specialized study of the motion of objects that are atomic/subatomic in size is called what?