What is the oxygen content of exhaled breath?

The correct choice regarding the oxygen content of exhaled breath is indeed 16%. When we breathe in atmospheric air, it typically contains about 21% oxygen. However, after the oxygen is utilized by the body for various metabolic processes, the air we exhale has a reduced oxygen concentration.

After the gas exchange process occurs in the lungs, where oxygen is absorbed into the bloodstream and carbon dioxide is released, the composition of exhaled breath shows that the oxygen content falls to approximately 16%. This reflects the consumption of oxygen by the body's tissues, illustrating the efficiency of the respiratory system and its role in maintaining the balance of gases. Understanding this helps in various medical and health-related scenarios, such as assessing respiratory function and the need for oxygen supplementation.