Across
- 3. Mixture of various decaying organic substances
- 5. an environment with air
- 6. Capable of being supported
- 7. To keep something in its original state
- 11. Trash on the ground
- 12. sun energy
- 13. Made without chemicals
- 15. buying or using less
- 19. Human-made gases containing chlorine and fluorine
- 21. an environment without air
Down
- 1. Capable of being broken down by bacteria and other decomposers.
- 2. An energy-rich substance (such as coal, oil, or natural gas)
- 4. To protect something
- 8. restored or replaced by natural process
- 9. A substance discharged into the air
- 10. Layer of gases surrounding a planet
- 14. To make something new out of a used object
- 16. The surroundings or conditions in which a person,animal or plant lives
- 17. a layer in the Earth's atmosphere; O3
- 18. The scientific study that deals with the relations of organisms to one another
- 20. The natural home or environment of an animal,plant or organism