The baby is used to getting what it needs through the placenta, which includes oxygen. The baby's lungs are initially filled with amniotic fluid.
The largest reservoir of carbon is in the ocean
I dont think i'm answering your question, but the sun turns into a red giant, and the more it gets bigger it gets, the more closer it is to the planets. Then eats up the the planets later on, and explodes. Dont know if im correct tho sorry