Why do we say we are breathing in oxygen when the atmosphere consists of Nitrogen — 78 percent Oxygen — 21 percent?

1 Answer
Feb 12, 2018

Because we cannot breathe nitrogen!

Explanation:

Our human body needs oxygen to make ATP, so that's why we say that we are breathing oxygen instead of nitrogen. Even though nitrogen is abundant in more than 3 times the amount of oxygen in the atmosphere, we cannot breathe it in our body, so we say that we breathe oxygen, as that's element that we need to make ATP for our body to use.