Question

What increases the rate of diffusion of oxygen into red blood cells in the lungs?
A. Air leaving the lungs is saturated with water vapor.
B. Air leaving the lungs still contains 16% oxygen.
C. Blood arriving in the lungs is saturated with oxygen.
D. Blood is taken away from the lungs as it circulates.

Answer 1

Answer:

Blood arriving in the lungs is saturated with oxygen.

Explanation:

Membrane surface area - the larger the surface area, the faster the rate of diffusion. The lungs normally have a very large surface area for gas exchange due to the alveoli. Because of the enormous number of alveoli (approximately 300 million in each human lung), the surface area of the lung is very large (75 m2). Having such a large surface area increases the amount of gas that can diffuse into and out of the lungs.