Final answer:
The alveoli are responsible for the exchange of gases in the respiratory system, where they transport oxygen to the bloodstream and remove carbon dioxide.
Step-by-step explanation:
The function of the alveoli is to facilitate gas exchange within the respiratory system. These tiny sac-like structures are where oxygen is transported to the bloodstream, and carbon dioxide is removed. When you inhale, air fills the alveoli, oxygen passes through their walls into the surrounding capillaries, and is then carried by red blood cells to the rest of the body. Conversely, carbon dioxide produced by cellular respiration is transported back to the alveoli via the blood, where it is expelled from the body through exhalation.