Here's why:

* Hypothalamus: This part of the brain acts as the body's thermostat. It receives information from temperature sensors in the skin and internal organs and sends signals to other organs to adjust body temperature.

* Autonomic Nervous System: This part of the nervous system controls involuntary functions like sweating, shivering, and blood vessel dilation/constriction, all of which play a role in regulating body temperature.

While other systems contribute, the nervous system is the control center for thermoregulation.