Why must the material composing our structure, like iron and calcium, have been recycled across multiple stellar generations?

Answer

The Sun is only old enough to have created elements up to iron, but bones require calcium, demanding more massive stars that burned out quickly.

The Sun is only capable of creating elements up to iron. Elements like calcium, required for bones, demand the lifecycle of larger, faster-burning stars that lived and died before the Sun ignited, necessitating prior recycling.

Why must the material composing our structure, like iron and calcium, have been recycled across multiple stellar generations?
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