Question

The air we inhale consists of approximately 21% oxygen.

• A. 10%
• B. 21%

Answer 1

The correct option is A

10%

The air that we inhale directly from the atmosphere contains around 21% oxygen. On the other hand, the exhaled air from lungs consists of a lesser percentage of oxygen, approximately around 13.6% to 16% but contains more of carbon dioxide. This is because oxygen is used by our body to generate energy by the process of respiration and carbon dioxide is produced as a waste product in this process.