Homeostasis

Homeostasis is like a thermostat in your house. It helps your body keep things at a comfortable level, even when the outside conditions change. For example, if it gets cold outside, your body can adjust to stay warm. It does this by releasing things like sweat to cool you down, and shivering to warm you up.
Homeostasis also helps your body keep other things like blood sugar, water, and pH levels balanced. All of these things need to be in a certain range in order for your body to stay healthy.

In short, homeostasis helps your body stay in balance, even when things around it change.