Question

Which of the following characteristics make the human lung an efficient respiratory surface?

• A. Thin walls for diffusion
• B. Large surface area
• C. Moist air sacs
• D. All of the above

Answer 1

The correct option is D All of the above

Human lungs are efficient respiratory surfaces because of the thin and large surface for easy diffusion, moist air sacs with mucus for dissolving the gases. In addition, the air sacs are surrounded by a network of blood capillaries with a good supply of blood so that more exchange of gases can happen.