Across
- 4. Place to dispose waste
- 5. Vanished or no longer living
- 6. Maintain in original state
- 9. Able to be maintained
- 10. To protect from harm
- 12. Relating to living matter
- 13. Convert to reusable material
- 16. Decayed material used as plant fertilizer
- 17. Envelope of gases surrounding Earth
- 18. To contaminate
- 19. A branch of Biology
Down
- 1. Reuse discarded material or objects
- 2. Natural home of an animal or plant
- 3. Toxic gas
- 4. Trash in a public place
- 7. Biological community of interacting organisms
- 8. Relating to the sun
- 11. Surroundings in which we live
- 14. Production and discharge of gas or radiation
- 15. Resource not depleted by use like water