Question

Lungs have a large number of alveoli for __________________ .

• A. Having spongy texture and proper shape
• B. More surface area for diffusion of gases
• C. More space for increasing volume of inspired air
• D. More nerve suply

Answer 1

Answer: (B)

More surface area for diffusion of gases

B. More surface area for diffusion of gases.

Solution: The structure of the alveoli maximizes their surface area to increase gas diffusion. Alveoli are tiny sacs at the end of bronchioles, they are so tiny yet abundant that help increasing their surface area to volume ratio. Breathing ensures that the oxygen concentration in the alveoli is higher than in the capillaries so oxygen moves from the alveoli to the blood. The exchange of gases occurs between the alveoli and blood in the capillaries that supply the lungs.