What is the function of the respiratory system?

The primary function of the respiratory system is indeed to provide oxygen to the blood. This process begins when air enters the lungs through inhalation. In the alveoli, tiny air sacs within the lungs, oxygen from the inhaled air diffuses across the alveolar membrane into the bloodstream, where it binds to hemoglobin in red blood cells. This oxygen-rich blood is then transported throughout the body to supply the cells and tissues, enabling them to perform vital metabolic processes that require oxygen.

While the respiratory system also plays a role in removing carbon dioxide from the blood, this function is closely linked to the delivery of oxygen, as the process of respiration involves both inhalation (bringing in oxygen) and exhalation (removing carbon dioxide). The other options, which include transporting nutrients and regulating body temperature, are functions of different systems in the body, such as the circulatory system and the integumentary system, respectively.