Across
- 4. Returning a natural area to a healthy state
- 6. The permanent destruction of wooded areas
- 8. A measure of the resources Earth has available
Down
- 1. When there are no more living members of a species
- 2. When pollutants travel up through food chains
- 3. To maintain an ecosystem in a healthy state
- 5. The contamination of soil, air, or water
- 7. A species at risk of extinction