Why do people who climb at such high altitudes need to acclimatize themselves?

c

Explanation:

The higher the peak, the more efficient our bodies must be at using oxygen, so the more we must acclimatize. The highest mountains in the world are over 8,000 meters (26,400′) and the air is so thin (low in pressure), it takes weeks for our bodies to even be able to survive at the altitudes where we camp