Across
- 2. Plants of a particular region
- 5. Without artificial chemicals
- 9. Energy made by the sun
- 14. Gas that plants and animals need to live
- 15. Forest with high rainfall
- 16. Use again
- 17. Convert something old into something else
- 18. A layer of gas found high in the atmosphere
- 19. Study of animals and plants in their environment
- 20. From nature
- 21. Good for the environment; also a color
Down
- 1. Mix of smoke and chemicals in the air
- 3. Rain with sulfuric acid
- 4. Animals of a particular region
- 6. An event that causes great damage
- 7. Weather in a place
- 8. Growing plants as food
- 10. Something that is naturally renewed
- 11. Not harmful to the environment
- 12. Poisonous chemicals from factories
- 13. Make smaller or less in amount
- 17. Things that are useful to humans