Explanation:
Fusion reaction is defined as a reaction in which two small nuclei combine together and result in the formation of a large nuclei along with release of huge amount of energy.
For example, [tex]^{2}_{1}H + ^{2}_{1}H \rightarrow ^{4}_{2}He[/tex] is a nuclear fusion reaction.
On the other hand, a fission reaction is defined as a reaction in which a large nuclei splits into two small nuclei along with release of huge amount of energy.
For example, [tex]^{238}_{92}U \rightarrow ^{234}_{90}Th + ^{4}_{2}He[/tex] is a nuclear fission reaction.
Therefore, in both these reactions it is common that energy is releasing due to conversion of mass into energy.
Thus, we can conclude that energy is released by converting mass into energy is one way that fission and fusion are similar.
