Susan is suffering from a high fever which region of the brain is responsible for controlling her body temperature

The correct answer is hypothalamus.

Explanation:

A small region of the brain, situated at the base of the brain, close to the pituitary gland is the hypothalamus. The hypothalamus plays an essential role in various activities like discharging hormones, monitoring the temperature of the body, regulating emotional responses, managing sexual behavior, and controlling appetite.  

Fever is the mechanism, which is considered to be a protective reaction by the body in response to the infectious disease. When any virus or bacteria get within the body and lead to tissue injury, then one of the responses of the immune system is to generate pyrogens. These are the chemicals, which are mediated towards the brain by the blood and disturbs the working of the hypothalamus, which monitors the temperature of the body.  

The pyrogens obstruct the heat-sensing neurons and instigate the cold-sensing ones, and the changing of these temperature radars misleads the hypothalamus into considering that the body is cooler, which causes the hypothalamus to elevate the temperature of the body more than the usual range, thus, resulting in a fever.  

what's the question?

it cools slower in the earth meaning the crystals have more time to form than lava on the surface