The reactant for nuclear fusion in all young stars is hydrogen. Specifically, it is the fusion of hydrogen nuclei (or protons) to form helium nuclei, which is the primary source of energy in stars.
The reactant for the nuclear fusion reaction in all young stars is hydrogen. More specifically, stars fuse hydrogen nuclei (protons) together to form helium nuclei, releasing a tremendous amount of energy in the process. This fusion reaction is known as the proton-proton chain.
