What is the primary nuclear fusion reaction occurring during a star's main sequence phase?

Answer

Fusing hydrogen ($ ext{H}$) into helium ($ ext{He}$)

For the majority of a star's life, known as the main sequence phase, the core activity involves fusing the lightest element, hydrogen, into the next simplest element, helium.

What is the primary nuclear fusion reaction occurring during a star's main sequence phase?
ElementprocessstarFusionnucleosynthesis