sentence2_structure: objects<>are<>atomic/subatomic$$$The specialized study of the motion of objects<>is called<>quantum mechanics
sentence1: Quantum mechanics is a way of describing interactions at very small scales of distance, the level of individual atoms, for instance, nuclei of atoms, or subatomic particles such as electrons or photons.
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?