Answer:
The statement that best describes nuclear fusion is;
Nuclei combine to form a heavier nucleus, releasing energy
Step-by-step explanation:
In nuclear fusion, we have the reaction of the nuclei of two or more atoms coming together (combining) to form heavier elements and subatomic particles such as protons and neutrons accompanied by the release or absorption in energy depending on the difference between the mass of the reactants and the products
Some nuclear fusion reaction require an input of energy and such reactions are therefore not spontaneous
The best option is nuclei (two or more nuclei) combine to form a heavier nucleus, releasing energy.