Question Detail
Question
In which direction does carbon dioxide diffuse at the alveolus?
Correct Answer
Option B is the correct answer.
Detailed Explanation
CO₂ diffuses out of the capillary blood (where pCO₂ is high at 45 mm Hg) into the alveolus (where pCO₂ is low at 40 mm Hg).
Hint
It moves down its concentration gradient, from high to low pressure.