1) (d) High altitude. IN high altitude has a extreme climate range from burning hot day to freezing nights. Also there are strong winds and the humidity is low which causes rapid dehydration. There is also extreme low air pressure, resulting in very little oxygen.

2) Short-term adaptation: When an individual ventures into a high altitude environment our body adjust to the lower oxygen. The individual will begin to breathe faster and more quickly adapt. The heart rate also increase to supply more oxygen to the tissue.

Facultative adaptation: When a person moves into a high-altitude environment, the human body responds to the stress by increasing the number of oxygen carrying blood cells.

Developmental adaptations: Many Indians from the high mountain valleys in Peru and Bolivia produce more hemoglobin in their blood and to increase their lung capability to better adapt to high-altitudes. Tibetans and Nepalese who live at high altitudes have broader arteries and capillaries which allow a much greater rate of blood flow increasing the amount of oxygen to the muscles.

(Face is red due to increased blood flow)

Cultural adaptation: Due to the llamas prowess in high-altitude, many mountain tribes use alpacas to help transport resources.

3) Studying human variation in this way can determine the certain genetic advantage or disadvantage we can use it to  diagnose, treat, or prevent illness. If we can isolated the part of DNA that gives certain Peruvians more hemoglobin it may be possible to be able to change our own DNA so we can produce more hemoglobin. Also if a population has a genetic disadvantage we can prepare for our offspring.

4) We shouldn't use race to understand the human variation due to adaptation. What we determine as a race changes constantly. Not to long ago, only strictly Americans were considered white in the USA now white blankets the Irish, Germans, and the French. Now several Latinos consider themselves white. Environmental influences should be the only way we understand human variation.