Across
- 2. To make dirty
- 5. Made by nature
- 6. To prevent waste
- 8. Fumes from vehicles
- 12. The air surround the earth
- 17. External conditions or surroundings
- 18. To use again
- 19. To process used good to make better
Down
- 1. Branch of Science that studies organisms and their environment
- 3. Place to dispose of trash
- 4. To keep safe
- 7. To be able to use continuously
- 9. Light and heat from the Sun
- 10. Protects the earth from ultraviolet rays
- 11. Decaying material used for fertilizer
- 13. The place where an organism lives
- 14. No longer living
- 15. Able to be again
- 16. Scattered Trash
- 17. Organisms and their environment working together