Final answer:
Most of the Sun's energy is produced by the process of nuclear fusion, which converts mass into energy through the fusion of hydrogen nuclei into helium nuclei in the core of the Sun.
Step-by-step explanation:
The energy of the Sun is produced primarily through the process of nuclear fusion. This process involves fusing protons, or hydrogen nuclei (^1H), into helium nuclei (^4He), specifically through a series of reactions known as the proton-proton cycle. These fusion reactions convert mass into energy, as expressed by Einstein's equation E=mc^2, demonstrating that mass is a form of energy. The reaction releases a tremendous amount of energy, as the resulting nucleus has less mass than the combined mass of the original protons. The Sun's core is where these reactions predominantly occur, releasing energy that eventually reaches Earth.