Question

which of the following substances diffuses out of the alveolus in the air during gas exchange? o₂ (oxygen) co₂ (carbon dioxide) n₂ (nitrogen)

Explanation:

During gas - exchange in the alveolus, oxygen diffuses into the blood and carbon - dioxide diffuses out of the blood into the alveolus to be exhaled. Nitrogen is mostly inert and does not participate significantly in gas - exchange.

Answer:

CO₂ (carbon dioxide)