Anuclear fission reaction and a nuclear fusion reaction are similar because both reactions
(1) form heavy nuclides from light nuclides
(2) form light nuclides from heavy nuclides
(3) release a large amount of energy
(4) absorb a large amount of energy

Both reactions release a large amount of energy is the statement that is correct about the similarity between a nuclear fission reaction and a nuclear fusion reaction.

A nuclear reaction is a procedure that leads to combining and modifying the nuclei of atoms, absorbing or releasing particles and energy according to each case.

Therefore, we can conclude that while in a fusion reaction two or more light nuclei unite, in a fission reaction a heavy nucleus breaks, both cause the release of energy.

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(3) release a large amount of energy

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.

Thus in the both the reactions energy is released.