The air at high altitude has a lower pO2 than air at sea level. Therefore, some competitive endurance athletes live at high altitudes to induce respiratory and hematopoietic adaptations (changes in blood components) that can improve performance at sea level. For example, within a few days at altitude, a person's normal ventilation rate will be 2-3 L/min higher than their sea level rate, and their blood will have more red blood cells and an increased level of 2,3-diphosphoglycerate, a substance produced by red blood cells that increases the P50 of hemoglobin. Explain why EACH of these physiological changes is necessary to acclimate to life at high altitudes, and speculate on how they could lead to improved performance of aerobic exercise at sea level (assuming that changes that occur at high altitudes will be maintained at sea level).