Where occurs the exchange of oxygen and carbon dioxide?

The exchange of oxygen and carbon dioxide primarily occurs in the alveoli and the capillaries. Alveoli are tiny air sacs located in the lungs where oxygen from inhaled air passes through their thin walls into the surrounding capillaries. This oxygen then binds to hemoglobin in red blood cells for transport to body tissues. At the same time, carbon dioxide, which is a waste product produced by metabolism in the body's cells, diffuses from the blood in the capillaries into the alveoli to be exhaled.

This specific interaction facilitates effective gas exchange, ensuring that the body receives the oxygen it needs to function properly while expelling carbon dioxide. Other options, while relating to the circulatory and respiratory systems, do not accurately represent the specific site of gas exchange. For instance, the heart is involved in pumping blood but does not directly engage in gas exchange itself, and arteries and veins primarily transport blood rather than facilitate the actual exchange of gases.