why we breathe oxygen and not something like carbon dioxide or nitrogen?

Question

why we breathe oxygen and not something like carbon dioxide or nitrogen?

In: 40

Answer 1

Oxidation.

Cells need oxygen so that it can react with sugar, which in turn makes energy available for that cell. Oxidation only works with oxygen, so things like nitrogen aren‘t useable.

Carbondioxide can be used for oxidation, but those reactions are more forced, so to speak.

It simply happens to be that oxygen is abundant and can be used as an easy way to release energy. Because it has worked life kept using it.