Answer 1

Nuclear fission and nuclear fusion can be differentiated as follows. 

	Nuclear fission	bNuclear fusion
Definition	Fission is the splitting of the heavy nucleus of a radioactive atom into smaller nuclei.	Fusion is the fusing of two or more lighter nuclei into a heavy nucleus.
Natural occurrence of the process	The process of nuclear fission does not normally occur in nature.	Fusion occurs in stars, such as the sun
Energy released	The energy released by fission is a million times greater than that released in chemical reactions, but is lower than the energy released by nuclear fusion.	The energy released by fusion is three to four times greater than the energy released by fission.