Question

what important traits of alveoli allow for highly efficient gas exchange in the lungs?
correct answer(s)
large number
oxygen - rich
large surface area
thin walls
incorrect answer(s)

Explanation:

Efficient gas exchange requires maximizing contact area and minimizing diffusion distance. A large number of alveoli creates a large total surface area, and thin walls (one cell thick) reduce the distance for gas diffusion. "Oxygen-rich" describes air in alveoli, not a trait of alveoli themselves.

Answer:

large number, large surface area, thin walls