What is the main process performed by the respiratory system?

The primary function of the respiratory system is to facilitate gas exchange, specifically by bringing in oxygen from the environment and removing carbon dioxide from the body. This process occurs in the lungs, where oxygen is absorbed into the bloodstream and carbon dioxide, a waste product of metabolism, is expelled during exhalation. The efficiency of this system is vital for maintaining cellular respiration, which is essential for energy production in the body.

Other processes mentioned in the choices, such as digesting food and absorbing nutrients, are functions of the digestive system; filtering blood and eliminating waste is carried out by the excretory system; and hormone production and secretion is the domain of the endocrine system. Each body system has its specific roles and functions, which highlights the importance of the respiratory system in maintaining overall health and homeostasis through its unique function of gas exchange.