Homeostasis

homeostasis maintains some conditions inside the body at a constant level.

Negative feedback mechanism responds to a change in a condtition and helps bring the condition back to normal level.

Osmoregulation controls how much water is lost in the urine, and so controls the amount of water lost in the body.

Thermoregulation keeps core body temp steady at around 37 degrees C. This is important because enzymes in the  main organs are most active at this temp.