Which best describes what forms in nuclear fusion?

two smaller, more stable nuclei
two larger, less stable nuclei
one smaller, less stable nucleus
one larger, more stable nucleus

one larger, more stable nuclei.

Explanation:

Nuclear fussion is the process of union of smaller atom nuclei into one single larger and more stable nucleus.

It is possible to combine two lighter (smaller) less stable nuclei to form one larger nucleus because the two ligher atoms may gain stability through nuclear fusion.

Those reactions are able to release a huge amount of energy.

A good example of nuclear fussion is what happens in the Sun. The energy of the Sun comes from a series of nuclear fussion reactions in which two hydrogen atoms fuse to form one helium atom plus energy.

The answer is D