Final answer:
Acclimatization is the process wherein the body adjusts to lower oxygen levels at high altitudes, leading to an increase in red blood cells and hemoglobin to efficiently transport oxygen. This helps prevent acute mountain sickness and allows people to partake in physical activities despite the harsh conditions.
Step-by-step explanation:
When a person is exposed to high altitudes, the decrease in atmospheric pressure and oxygen levels can lead to a condition known as acute mountain sickness (AMS). To adapt, the body undergoes a process called acclimatization, which is the respiratory system's adjustment to chronic exposure to low oxygen levels. Over about 10 days, the kidneys increase the production of erythropoietin (EPO), which stimulates the creation of more red blood cells (erythrocytes). This leads to a higher hemoglobin level in the blood, enabling more efficient oxygen transportation despite the lower oxygen saturation of each hemoglobin molecule. Indigenous populations, such as those in the Andes and Tibet, have developed unique adaptations to such environments, demonstrating human variation in response to environmental challenges.