Final answer:
The exchange of CO2 and O2 takes place in the alveoli, which are the sac-like structures at the end of bronchioles in the lungs. This process provides oxygen to the body and removes carbon dioxide. a) alveoli
Step-by-step explanation:
The exchange of CO2 (carbon dioxide) and O2 (oxygen) occurs in the alveoli (option a). The alveoli are tiny sac-like structures at the ends of the bronchioles in the lungs where the pulmonary gas exchange takes place. Air enters the lungs via the trachea, moves through the bronchi and bronchioles, and finally reaches the alveoli. These structures are surrounded by capillaries where oxygen is absorbed into the blood, and carbon dioxide is released from the blood to be exhaled.
Bronchioles are airways that extend from the main bronchus to the alveolar sac, but they do not facilitate the gas exchange themselves. Instead, they lead to the alveolar ducts, which connect to alveolar sacs comprised of alveoli. It's in these alveoli that the crucial gas exchange between the lung and blood actually occurs, providing the body with oxygen and removing carbon dioxide.