What is the primary function of the respiratory system?

The primary function of the respiratory system is to facilitate gas exchange, which is vital for the survival of an organism. This system allows oxygen to enter the bloodstream while simultaneously removing carbon dioxide, a waste product of metabolism. The process of respiration occurs in the alveoli of the lungs, where oxygen diffuses from the air into the blood, and carbon dioxide diffuses from the blood into the air to be exhaled. This exchange is essential for maintaining the body’s oxygen levels, supporting cellular functions, and ensuring overall homeostasis.

While other options may relate to functions of different systems in the body—such as the endocrine system, which is responsible for hormone production; the immune system, which plays a role in filtering toxins; and the thermoregulatory processes managed by the skin and circulatory system—none encompass the primary role of the respiratory system as effectively as gas exchange does.