What is the primary function of the respiratory system?

The primary function of the respiratory system is to facilitate breathing and gas exchange. This involves the intake of oxygen from the environment and the expulsion of carbon dioxide, a waste product of metabolism, from the body. The respiratory system includes structures such as the lungs, trachea, and diaphragm, which work together to ensure that oxygen enters the bloodstream and carbon dioxide is removed efficiently.

Breathing involves the process of inhalation, where air is drawn into the lungs, and exhalation, where air containing carbon dioxide is expelled. This exchange is crucial for maintaining the body's homeostasis, as oxygen is vital for cellular respiration, which provides energy for bodily functions. Through this process, the respiratory system plays a key role in sustaining life by ensuring that tissues receive the oxygen they need while removing harmful carbon dioxide.

Other systems mentioned in the options, such as those for temperature regulation or hormone production, do not pertain directly to the main role of the respiratory system, which is specifically related to the management of gases within the body. Similarly, the circulatory system is responsible for pumping blood, not the respiratory system. This focus on gas exchange highlights the unique and essential nature of the respiratory system's contributions to overall health and function.