1.1. A mountaineer hikes up a mountain. 

With an increase in altitude there is a decrease in temperature.

Describe the homeostatic mechanism that will regulate the mountaineers' body temperature near the top of the mountain.

1.2. When hiking in extremely cold conditions, it is very important that mountaineers wear waterproof gloves that are properly insulated to avoid frostbite in their fingers and hands.

Frostbite (pictured above) is damage to the skin and tissue when exposed to very low temperatures. Severe frostbite can cause tissue death and in extreme cases, amputation of fingers and toes is the only course of action doctors can take. 

Deduce the reason why these gloves would prevent frostbite.

1.3. The tissue death caused by severe frostbite is known as gangrene. In such cases, the affected parts must be amputated.

Use your knowledge of skin structure and blood vessels to explain why gangrene is more likely in extremities, such as fingers and toes.

1.4. Prolonged exposure to extremely cold conditions leads to hypothermia. This occurs when a dramatic decrease in body temperature leads to a decrease in metabolism, which in turn results in less heat energy being released leading to a further drop in body temperature.

In this sense, hypothermia is an example of a positive feedback loop.

Explain why positive feedback loops cannot be considered a homeostatic mechanism.