Across
- 3. The natural home of an animal, plant, or other organisms
- 5. Decayed organic material used as a plant fertilizer
- 7. Source that is not depleted
- 8. To reuse materials
- 10. It differs from oxygen in having three atoms in its molecule
- 11. The envelope of gases surrounding the earth
- 12. To reuse a material but making it into something of higher quality
- 14. The surroundings or conditions in which a person, animal, or plant lives or functions
- 16. Determined by the sun
- 18. Relating to a state of being maintained
Down
- 1. Contaminated with harmful and poisonous substances
- 2. A place to dispose of materials
- 4. Trash, such as paper, cans, and bottles
- 6. No longer alive, gone
- 9. A branch of biology that deals with the ecosystem
- 13. To maintain in its original state
- 15. The production and discharge of gas or radiation
- 17. Relating to or derived from living matter