Which organs are primarily responsible for gas exchange in mammals?

Gas exchange in mammals primarily occurs in the lungs. The lungs are specialized organs designed to facilitate the exchange of oxygen and carbon dioxide between the air and the bloodstream. When mammals inhale, oxygen-rich air fills the alveoli, tiny air sacs in the lungs. Oxygen then diffuses across the thin walls of the alveoli and into the blood in the surrounding capillaries. At the same time, carbon dioxide, which is a waste product produced by metabolism, diffuses from the blood into the alveoli to be exhaled.

The other organs listed, while vital for different physiological functions, do not play a direct role in gas exchange. The heart is primarily responsible for pumping blood throughout the body, the liver has essential roles in metabolism and detoxification, and the kidneys are primarily involved in filtering blood and producing urine. Thus, the lungs stand out as the main site for gas exchange in mammals.