Question

if there is 21% of oxygen but 78% of nitrogen in the air then when we inhale does the nitrogen go in too? if yes, then what happens to it?

Answer 1

The air we breathe contains oxygen, nitrogen, carbon dioxide, water and trace elements. We breathe all together. But after reaching to the lungs, only oxygen enters into the alveolar blood flow. All other elements of air mixed with carbon dioxide come out of the body when we exhale.