ANATOMY

Detailed explanation-1: -True. The air that we inhale contains around 21% oxygen. This oxygen is used by the body for respiration and therefore the exhaled has less percentage of oxygen (13.6% to 16%).

Detailed explanation-2: -The percentage of oxygen in inhaled air is 21%.

Detailed explanation-3: -Atmospheric air is rich in nitrogen which is about 78%. Oxygen constitutes 20% of the atmospheric air. Therefore the inhaled air consists of 20% of oxygen.

Detailed explanation-4: -The air which we breathe in and breathe out is not pure oxygen or carbon dioxide respectively. Inhaled air is a mixture of different gases present in the atmosphere. It contains around 78% nitrogen, 21% oxygen, 0.04% of carbon dioxide and other gases.

Detailed explanation-5: -It’s a mixture of different gases. The air in Earth’s atmosphere is made up of approximately 78 percent nitrogen and 21 percent oxygen.