Question

What causes oxygen to diffuse from the lungs into the capillaries?
A) Blood from the pulmonary arteries is high in oxygen
B) The oxygen concentration is lower in the capillaries
C) The oxygen concentration is lower in the lungs
D) There is an equal oxygen concentration in the lungs and capillaries

Answer 1

Answer:

B.

Explanation:

In a process called diffusion, oxygen moves from the alveoli to the blood through the capillaries (tiny blood vessels) lining the alveolar walls. Once in the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells.