Across
- 4. any material in nature that people use and value
- 6. surroundings
- 7. semidry grasslands or prairies
- 9. resources Earth replaces naturally
- 10. permanently frozen layers of soil
- 11. a group of plants and animals that depend on each other for survial
- 12. clearing of trees
- 13. to die out
- 15. areas of tall grasses and scattered trees and shrubs
- 17. seasonal winds that bring either dry or moist air
Down
- 1. a place where a plant or animal lives
- 2. production of electricity from water
- 3. spread of desertlike conditions
- 5. planting of trees to replace lost forestland
- 8. resources formed from remains of ancient plants
- 14. resources that cannot be replaced
- 16. decayed plant or animal matter