Question

the _____ holds protons together with the strongest force in the universe. strong nuclear force nucleus belt theory of relativity atomic band

Explanation:

The strong nuclear force is the strongest fundamental force in the universe and it binds protons and neutrons together in the nucleus of an atom. The other options are not related to holding protons together with the strongest force. "Nucleus belt", "atomic band" are not real scientific terms in this context, and the theory of relativity deals with space - time and gravity, not with nuclear forces.

Answer:

A. strong nuclear force