Across
- 2. permanent frozen layers of Earth
- 7. earth replaces naturally
- 10. materials in nature that people use and value
- 11. nonrenewable; formed from remains of plants and anmimals
- 13. average weather conditions over a long period of time
- 16. tall made of rock, snow at top
Down
- 1. group of plants and animals that depend on each other
- 3. short term changes in the air
- 4. spread of desert conditions
- 5. decayed plant or animal matter
- 6. climate type that is very dry and hot
- 8. seasonal winds; bring dry or moist air
- 9. place where plants or animals live
- 12. air masses with different temperatures meet
- 14. to die out
- 15. effect of environmental change