What is negative feedback, and how does this process to keep values (like body temperature) constant or within a small range of values?

Negative feedback mechanism may be defined as the system of the body in which the final output reduces the process and result in the less output. Negative feedback mechanism is important for the regulation of homeostasis.

The negative feedback mechanism maintains the constant body temperature. The change in body temperature is sensed by the receptors. The low body temperature initiates the hypothalamus to increase the physiological process.    The blood vessels narrow, body start shivers and hormone stimulation increases body temperature. When the body temperature become normal, the hypothalamus will no longer be stimulated and stop its effect.