The iron in your blood
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