If these are the percentage of gases you breathe in, what will the percentage of the gases you breathe out be? Nitrogen = 78% Oxygen = 21% Carbon Dioxide = 0.04%

A: Nitrogen = 78% Oxygen = 21% Carbon Dioxide = 0.04%

B: Nitrogen = 78% Oxygen = 16% Carbon Dioxide = 4%

C: Nitrogen = 99% Oxygen = 0% Carbon Dioxide = 0.04%

D: Nitrogen = 50% Oxygen = 25% Carbon Dioxide = 25%

B: Nitrogen = 78% Oxygen = 16% Carbon Dioxide = 4%

Explanation:

We, as humans, undergo the process of cellular respiration in order to release energy for use. However, we require oxygen (O2) to perform this process of respiration and release carbon dioxide (CO2) as a waste product. The oxygen is obtained when we breathe in air, which contains the following gases in the following proportions:

Nitrogen = 78% Oxygen = 21% Carbon Dioxide = 0.04%

However, a part of the oxygen component of these air is used for cellular respiration. Hence, the percentage of oxygen in the exhaled air will reduce while the percentage of carbon dioxide will increase. The composition of gases in the exhaled air is as follows:

Nitrogen = 78% Oxygen = 16% Carbon Dioxide = 4%

Note that, oxygen reduced (21%-16%), and carbon dioxide increased (0.04%-4%). Nitrogen is not used in cellular respiration, hence, the composition does not change.