What is the main function of the respiratory system?

The primary function of the respiratory system is the exchange of gases, specifically oxygen and carbon dioxide, between the body and the environment. This process occurs in the alveoli of the lungs, where oxygen from inhaled air diffuses into the bloodstream, and carbon dioxide, a waste product produced by cellular metabolism, diffuses out of the blood to be exhaled.

The significance of this gas exchange cannot be overstated; oxygen is vital for cellular respiration, which generates the energy necessary for all bodily functions. At the same time, the removal of carbon dioxide is crucial because its buildup can lead to respiratory acidosis and other health issues.

The respiratory system also plays roles in other processes such as regulating pH levels in the blood and facilitating vocalization, but these are secondary to its primary function of gas exchange. This illustrates why the correct choice emphasizes the exchange of gases as the essential role of the respiratory system.