Stardust or the elements in our bodies?

Question

How do we know we are made of stardust? As our cells divide, are our atoms repurposed from existing materials or spontaneously generated? Do we consume materials after we are born that contain elements that were in stars? This I would understand. Or, as our cells are initially dividing after conception, but before birth, are we already repurposing existing materials to grow?

Answer 1

All of the non-hydrogen atoms in our bodies are "stardust", in the sense that only hydrogen and helium were generated in the Big Bang and all heavier elements were created in the interior of stars, and then ejected in supernovae.

Answer 2

Growth is only possible when material is acquired from the environment. An organism grows by taking in material from its surroundings and incorporating that material (atoms) into new cells.

Refer to a basic explanation of the evolution of stars to understand that fusion in stars creates the heavier elements. Look here:

https://www.nasa.gov/audience/forstudents/9-12/features/stellar_evol_feat_912.html

Yes, we come from the material created by stars.