Final answer:
Health depends on maintaining homeostasis, which is the body's ability to keep stable internal conditions despite external changes. Homeostasis involves constant adjustments and is maintained through feedback mechanisms like the concentration of urine in response to hydration levels.
Step-by-step explanation:
Health depends on the body maintaining homeostasis, and relatively stable internal conditions under fluctuating environmental conditions. Homeostasis is the process by which the body makes constant adjustments to changes and maintains equilibrium by ensuring body functions remain within a certain range. This ability to maintain a stable internal environment despite a changing external environment is not only about protecting against temperature changes but includes other aspects such as fluid balance.
For instance, if you are dehydrated, your body responds to maintain homeostasis by concentrating your urine to preserve water. This is an example of a homeostatic process. Homeostasis is maintained through mechanisms like negative feedback, which involves responses that keep a variable close to a set value or normal level.