AP BIOLOGY

Detailed explanation-1: -The amount of inhaled air contains 21% of oxygen and 0.04% of carbon dioxide, while the air we breathe out contains 16.4% of oxygen and 4.4% of carbon dioxide. This is because our cells use oxygen from the inhaled air to release energy and give out carbon dioxide as a byproduct.

Detailed explanation-2: -The air in the lungs has a higher concentration of oxygen than that of oxygen-depleted blood and a lower concentration of carbon dioxide. This concentration gradient allows for gas exchange during respiration.

Detailed explanation-3: -We inhale: nitrogen – 78% oxygen-21% other gases – 1%

Detailed explanation-4: -The highest oxygen concentration within the body is in the pulmonary veins. They mark the end of the pulmonary circulation path, where blood moves into the left atrium.

Detailed explanation-5: -60% O2 (upper limit for indefinite human survival), rest a mix of Nitrogen and other gases with a biome similar to earth.