MICROANATOMY

Detailed explanation-1: -Oxygen only makes up about 21% of air. About 78% of the air you breathe is made up of another gas called nitrogen. There are also tiny amounts of other gases like argon, carbon dioxide and methane.

Detailed explanation-2: -Oxygen makes up about 21% of the air we breathe. There is a perfect amount of oxygen in the atmosphere: enough for our lungs to absorb into our blood, but not enough to damage our tissues. The trillions of cells in our bodies use oxygen to break down molecules absorbed from the food we eat.

Detailed explanation-3: -The air in Earth’s atmosphere is made up of approximately 78 percent nitrogen and 21 percent oxygen.

Detailed explanation-4: -The atmospheric air consists of 78% of nitrogen, 21% of oxygen, 0.04% of carbon dioxide and 0.93% of argon and other inert gases.

Detailed explanation-5: -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%).