A
Splitting of a heavy nucleus into smaller nuclei
B
Loss of an electron from an atom
C
Emission of alpha particles only
D
Combining of light nuclei into a heavier one
Correct Answer: Option A — Splitting of a heavy nucleus into smaller nuclei
Explanation:
Nuclear fission is a process in which a heavy atomic nucleus splits into two or more smaller nuclei, releasing a significant amount of energy along with additional neutrons that can sustain a chain reaction.