Question

Which describes nuclear fusion?

Answer 1

The first one, when two nuclei combine. 

Answer 2

Answer:

The correct choice is

The nuclei of two atoms combine to form a larger nucleus.

Explanation:

Nuclear fusion is defined as the process in which the nucleus of two smaller  atoms combine together to form a larger nucleus and in the process of combining the two smaller nuclei, large amount of energy is released. An example of such a process is fusion reaction taking place inside sun and stars.