What is the primary function of the lungs in the human body?

The primary function of the lungs in the human body is to exchange gases, specifically to take in oxygen and expel carbon dioxide. This gas exchange occurs in the alveoli, tiny air sacs in the lungs where oxygen from inhaled air passes into the bloodstream, and carbon dioxide, a waste product produced by cells during metabolism, is released from the blood to be exhaled.

While removing waste carbon dioxide from the bloodstream is an important function of the lungs, it's part of the broader gas exchange process. The lungs do not directly remove carbon dioxide from the blood; instead, they facilitate oxygen uptake and carbon dioxide release through breathing. Therefore, the emphasis should be on the gas exchange process itself as the lungs primarily work to ensure that oxygen enters the body and carbon dioxide is expelled.

The other options, such as regulating body temperature and filtering toxins from the bloodstream, are not primary functions of the lungs. The body has other systems, such as the skin and the liver, that handle temperature regulation and detoxification, respectively. Thus, the most accurate description of the lungs' primary function centers on their role in the exchange of oxygen and carbon dioxide.