Before external respiration occurs,the concentration or partial pressure of carbon dioxide in the alveoli is _____ than in the pulmonary capillaries.
A)higher
B)lower
C)no different

Question

Quizplus · Accepted Answer

Before external respiration occurs, the partial pressure of carbon dioxide in the alveoli is lower than in the pulmonary capillaries. This gradient drives the diffusion of carbon dioxide from the capillaries into the alveoli during external respiration.

Before External Respiration Occurs,the Concentration or Partial Pressure of Carbon