Question

Which of the following best explains the passage of air across alveolar membranes? * A) active transport, through moist, thin epithelial membranes B) osmosis, through moist, thin epithelial cells C) diffusion, through moist, thin epithelial cells D) diffusion, through dry, thin epithelial cells

Answer 1

The correct option is C) diffusion, through moist, thin epithelial cells. Gases transport from sites with high pression (high gas concentration) to sites with low pression (where there is few or no gas). Thus, gas enters the cell, and it diffuses following this principle. Also, moist is very important to allow this movement, it facilitates it.