AP BIOLOGY

Detailed explanation-1: -The alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out. Oxygen breathed in from the air passes through the alveoli and into the blood and travels to the tissues throughout the body.

Detailed explanation-2: -Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them.

Detailed explanation-3: -In the lungs, air passes through the branching bronchi, reaching the respiratory bronchioles, which house the first site of gas exchange. The respiratory bronchioles open into the alveolar ducts, alveolar sacs, and alveoli.