2.78 understand that homeostasis is the maintenance of a constant internal environment and that body water content and body temperature are both examples of homeostasis

Homeostasis is the regulation of conditions inside the body. For example osmoregulation is the control of water levels in the body. Temperature regulation also needs to take place (as body process work best at 37 degrees) it is called thermoregulation. An example is when you are hot you sweat- so the heat is absorbed from your skin- and when you are cold you body hairs stick out- to trap air as a layer of insulation.