External respiration requires a higher oxygen concentration in the _____ than in the _____.
A) blood; lungs
B) blood; cells
C) cells; blood
D) lungs; blood

Question

Quizplus · Accepted Answer

External respiration is the process of exchanging gases between the lungs and the blood. During this process, oxygen diffuses from the lungs into the bloodstream, while carbon dioxide diffuses from the bloodstream into the lungs. Therefore, a higher oxygen concentration is required in the lungs (where it is being taken up by the blood) than in the blood (where it is being transported to the cells). Thus, the correct answer is D) lungs; blood.

External Respiration Requires a Higher Oxygen Concentration in the _____