the silicon in your computer, the oxygen that we breathe, all of those

elements were actually synthesized inside stars. Stars form from the collapse of a

cloud and

basically as soon as fusion starts taking place (hydrogen to helium)

the star finds peace and finds stability

and that's what we call the stars the main sequence and it spends the

majority of its time

and then depending on its mass you can actually

start fusing heavier and heavier elements. Thats in fact

what keeps stars fighting against gravity

the fact that as they fuse elemtns actually those reactions generate heat

but of course once you start off using progressively heavier elements and you

get into iron

those reactions can no longer give you heat at that point the star has lost

its battle against gravity and has no other fate but to collapse