5. every star starts with an initial mass of hydrogen. each atom of hydrogen has one proton and one neutron. how are the total number of protons and neutrons conserved as a star ages and undergoes continuous nucleosynthesis

See below.

Explanation:

As this hydrogen and helium began to form in the early universe, there were some areas where it was denser than in others. Gravity took over and eventually these atoms were pulled together into massive clouds gas in the vastness of space. Once these clouds became large enough, they were drawn together by gravity with enough force to actually cause the atomic nuclei to fuse, in a process called nuclear fusion. The result of this fusion process is that the two one-proton atoms have now formed a single two-proton atom.  So the number of protons is the same, but the number of atoms change! In other words, two hydrogen atoms have begun one single helium atom.