What is the primary function of the respiratory system?

The primary function of the respiratory system is to exchange gases between the body and the environment. This crucial process involves the inhalation of oxygen-rich air into the lungs, where oxygen is transferred into the bloodstream and delivered to cells throughout the body. Simultaneously, carbon dioxide, a waste product of cellular metabolism, is collected from the blood and expelled from the body during exhalation. This gas exchange is vital for maintaining the body’s cellular functions and overall metabolism, ensuring that tissues receive the oxygen they need to produce energy while removing toxins like carbon dioxide.

The other functions listed, while important, do not primarily define the role of the respiratory system. For example, the filtering and detoxification of blood is primarily the role of the kidneys and liver, nutrient absorption is a function associated mainly with the digestive system, and support for the immune response is typically managed by the lymphatic and immune systems, despite some involvement from respiratory structures. Thus, the clear and direct connection of gas exchange with the respiratory system makes it the correct choice.