AP BIOLOGY

Detailed explanation-1: -Bronchioles end in tiny air sacs called alveoli, where the exchange of oxygen and carbon dioxide actually takes place. Each person has hundreds of millions of alveoli in their lungs.

Detailed explanation-2: -These are called alveoli. They inflate when a person inhales and deflate when a person exhales. During gas exchange oxygen moves from the lungs to the bloodstream. At the same time carbon dioxide passes from the blood to the lungs.

Detailed explanation-3: -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-4: -Oxygen and carbon dioxide move across cell membranes via simple diffusion, a process that requires no energy input and is driven by differences in concentration on either side of the cell membrane.