Question

A unique feature common to the alveoli of lungs and the villi of the intestine is that both

• A. Have ciliated columnar epithelium
• B. Are suited for diffusion of gases
• C. Provide a large surface area
• D. Have a rich supply of blood vessels and lymph ducts.

Answer 1

The correct option is C

Provide a large surface area

Alveoli are tiny, circular air sacs which are important because they significantly increase the respiratory surface area of the lungs. Similarly, in the intestine, the villi greatly increase the surface area for absorption of nutrients. Due to the many walled surfaces of the alveoli, the lungs of a single person have a surface area that is approximately the size of a tennis court!