Answer:
Muscles can also receive messages from the brain when the body temperature decreases. They respond by shivering. Shivering causes the muscles to contract and relax quickly. This process generates heat.
Answer:
Homeostasis typically involves negative feedback loops that counteract changes of various properties from their target values, known as set points. In contrast to negative feedback loops, positive feedback loops amplify their initiating stimuli, in other words, they move the system away from its starting state.
The egg shell would be most representative of the Earth's Mantle or "Crust", the yolk and white would represent the molten metal inside the earths core I assume.