The atoms, the iron in your blood calcium in our bones and oxygen for our breath all come from the stars.

WHERE did the atoms in our bodies come from? The answer is that the iron in our blood, the calcium in our bones, the oxygen that fills our lungs each time we take a breath, all were forged in the furnaces of stars which lived and died long before the Earth was born.

The story of the origin of the chemical elements is one of the crowning achievements of 20th-century science. 
Read:  Element Genesis, Yuko Mochizuki