Across
- 2. disappearance of species
- 4. area of tall grasses
- 5. formed from plant, animal
- 8. clearing of trees
- 9. wind blows same direction
- 14. frozen layers soil
- 15. planting trees
- 16. material people use
- 17. surroundings
- 18. seasonal dry or moist air
- 19. cannot be replaced
- 20. plant, animal living together
Down
- 1. replaces naturally
- 3. a plant or animal lives
- 6. large streams surface water
- 7. a region's average weather
- 10. decayed plant or animal
- 11. spread desertlike conditions
- 12. the short-term changes in air
- 13. place two air masses meet