How is fission different from a simple chemical reaction?

A. fission reactions run out of control, while chemical reactions are controlled
B. protons cause fission reactions, while chemical reactions involve electrons
C. atoms are split into smaller pieces during fission
D. fission can happen with radioactive forms atoms

C. atoms are split into smaller pieces during fission

This is a key difference between nuclear fission and simple chemical reactions, where molecules are rearranged but not split into smaller pieces.