Which best describes what forms in nuclear fission?
a. two smaller, more stable nuclei
b. two larger, less stable nuclei
c. one smaller, less stable nucleus
d. one larger, more stable nucleus

A. two smaller, more stable nuclei

Explanation: Nuclear fusion is a process which involves the conversion of two small nuclei to form a heavy nuclei along with release of energy.

Nuclear fission is a process which involves the conversion of a heavier nuclei into two or more small and stable nuclei along with the release of energy.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.