What is the main function of the respiratory system? a. to exchange oxygen and carbon dioxide gases within the body b. to protect the body against foreign substances, such as bacteria and viruses c. to send signals from one part of the body to other parts of the body d. to break down food into nutrients that can be circulated throughout the body

The respiratory system's main function is to exchange oxygen and carbon dioxide gases within the body. The organs that make up the respiratory system include the nose, pharynx and larynx, the trachea, bronchi, and the lungs. Each of these organs help with the process of breathing and/or the exchanging of gases within them.  :)

your answer will be a. sorry if im wrong: )