Which process produces the energy that allows the stars of the universe to radiate visible light

Nuclear fusion.

Explanation:

Nuclear fusion is the process in which atomic nuclei colide to form a new nucleus with higher atomic mass.

The fusion process reduces the total mass of the particles involved, wich means that energy will be produced, according to the mass-energy equivalence equation: E = mc².

This energy will promote electronic transitions that will lead to visible light emission.

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.