Question

1. choose the best answer. the _ is the total community of living organisms and their environment. ecosystem erosion population tectonic equilibrium 9. choose the best answer. the gradual wearing down of the earths surface over a period of time by physical forces is called _ urbanization equilibrium erosion ecosystem tectonic

Explanation:

1. An ecosystem is defined as the total community of living organisms and their environment.
2. Erosion is the gradual wearing - down of the Earth's surface by physical forces.

Answer:

1. ecosystem
2. erosion