What best describes the primary function of the respiratory system?

The primary function of the respiratory system is to provide the body with oxygen. This is accomplished through the process of respiration, where air is inhaled into the lungs, and oxygen from that air is exchanged for carbon dioxide in the bloodstream. Oxygen is essential for cellular respiration, which is the process by which cells produce energy. Without adequate oxygen intake, the body’s cells cannot function properly, leading to serious health issues.

While removing carbon dioxide is a critical aspect of the respiratory system, it is primarily a byproduct of the oxygenation process. The focus of the respiratory system's primary role is to ensure that oxygen is supplied to the body. Transporting nutrients is a function more associated with the circulatory system, and regulating body temperature involves other systems and mechanisms rather than the primary function of the respiratory system.