Final answer:
At higher altitudes, the body produces more 2,3 BPG to facilitate the release of oxygen from hemoglobin.
Step-by-step explanation:
When a person ascends to higher altitudes, the oxygen concentration in the air decreases. This leads to a lower partial pressure of oxygen, making it more difficult for oxygen to bind to hemoglobin in the lungs. As a result, the body responds by producing more 2,3-bisphosphoglycerate (2,3 BPG) by erythrocytes. 2,3 BPG promotes the dissociation of oxygen from hemoglobin, allowing the release of oxygen to the tissues.