Here's the breakdown:

* Stars are powered by nuclear fusion, a process where lighter atomic nuclei combine to form heavier nuclei, releasing enormous amounts of energy.

* The most common fusion reaction in stars like our Sun is the proton-proton chain, where four hydrogen nuclei (protons) fuse together to create one helium nucleus.

This process is incredibly powerful, producing the light and heat that we see from stars. While it's not the only element stars produce, helium is the primary product of the initial fusion reactions that power stars.