AP BIOLOGY

Detailed explanation-1: -Once in the lungs, oxygen is moved into the bloodstream and carried through your body. At each cell in your body, oxygen is exchanged for a waste gas called carbon dioxide. Your bloodstream then carries this waste gas back to the lungs where it is removed from the bloodstream and then exhaled.

Detailed explanation-2: -The lungs are responsible for the excretion of gaseous wastes, primarily carbon dioxide from cellular respiration in cells throughout the body. Exhaled air also contains water vapor and trace levels of some other waste gases. The paired kidneys are often considered the main organs of excretion.

Detailed explanation-3: -The main waste gas excreted by the lungs is carbon dioxide, which is a waste product of cellular respiration in cells throughout the body. Carbon dioxide is diffused from the blood into the air in the tiny air sacs called alveoli in the lungs (shown in the inset diagram).

Detailed explanation-4: -CO2 is transported in the bloodstream to the lungs where it is ultimately removed from the body through exhalation. CO2 plays various roles in the human body including regulation of blood pH, respiratory drive, and affinity of hemoglobin for oxygen (O2).

Detailed explanation-5: -Excretion is the process of removing wastes and excess water from the body. Recall that carbon dioxide travels through the blood and is transferred to the lungs where it is exhaled. In the large intestine, the remains of food are turned into solid waste for excretion.