Answer: Maintaining equilibrium on Earth.
Explanation:
The biogeochemical cycles and geochemical cycles maintains equilibrium on earth by supplying the desired material required for many processes on earth.
The elements such as carbon, nitrogen and phosphorous recycle on earth and provides these nutrients to the plants and animals.
These nutrients are recycled again and again to maintain balance on earth.
Definition-A formation of new chemical substances.
Example- Sugar undergoes a chemical change when it is cooked to make caramel. :3
Hope I helped! Sorry if it's bad.