Which of the following actions occur during the process of fusion? 1.)atoms are divided 2.)atoms are broken apart 3.) atomic nuclei are united 4.)atomic nuclei are split

3.) atomic nuclei are united

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 if a heavier nuclei is being formed from two smaller nuclei, this is a nuclear fusion reaction.