Hemoglobin A) plays a critical role in determining the total amount of O₂ that is exchanged because it acts as a storage depot, removing dissolved O₂ and thus keeping the PO₂ low so that net diffusion is allowed to continue. B) combines only with O₂ . C) is found in erythrocytes. D) both (a) and (c) above. E) all of these answers.

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Quizplus · Accepted Answer

Hemoglobin is a molecule found in erythrocytes (red blood cells) and plays a critical role in determining the total amount of oxygen that is exchanged because it acts as a storage depot, removing dissolved oxygen and thus keeping the partial pressure of oxygen low so that net diffusion is allowed to continue. Therefore, choice (a) and (c) are both correct. Hemoglobin also combines specifically with oxygen, making choice (b) incorrect. Therefore, the best choice is (D) both (a) and (c) above.