Question

Lungs have a large number of alveoli for

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

Answer 1

The correct option is C More surface area for diffusion of gases

Alveoli

Alveoli are tiny air sacs present in the lungs and are responsible for gaseous exchange. They measure 500 mms each and there are about 400 million alveoli inside the lungs. The alveoli have irregular shapes and are balloon-like.

The rate of diffusion of gases is dependent upon surface area. Hence the diffusion of $O_2$ and $C{O}_2$ across the surface of alveoli will be more quicker due to the large surface area provided by the alveoli.

Final answer
(B) More surface area for diffusion of gases