If the partial pressure of oxygen in the lungs is 100 torr and in the tissues is 20 torr, how does this affect hemoglobin's oxygen affinity?

• A. Hemoglobin has higher oxygen affinity in the lungs due to higher partial pressure of oxygen.
• B. Hemoglobin has higher oxygen affinity in the tissues due to lower partial pressure of oxygen.
• C. Hemoglobin has lower oxygen affinity in the lungs due to higher partial pressure of oxygen.
• D. Hemoglobin's oxygen affinity is unaffected by changes in partial pressure of oxygen.

Answer: (A)