AP BIOLOGY

Detailed explanation-1: -Final answer: The incorrect statement is “They maintain the shape and surface tension of the air sac”

Detailed explanation-2: -Solution : Alveoli have a large surface area with very thin walls which is richly supplied with blood vessels and are always moist.

Detailed explanation-3: -Each alveolus is cup-shaped with very thin walls. It’s surrounded by networks of blood vessels called capillaries that also have thin walls. The oxygen you breathe in diffuses through the alveoli and the capillaries into the blood.

Detailed explanation-4: -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.