Earth Day

6. the surroundings or conditions in which a person, animal, or plant lives or operates
7. convert (waste) into reusable material
9. organic material used as a plant fertilizer
10. reuse (discarded objects or material) in such a way as to create a product of higher quality or value than the original
12. able to be maintained at a certain rate or level
14. the branch of biology that deals with the relations of organisms to one another and to their physical surroundings
16. a colorless unstable toxic gas with a pungent odor and powerful oxidizing properties, formed from oxygen by electrical discharges or ultraviolet light
17. having no living members; no longer in existence
18. trash, wastepaper, or garbage
19. energy derived from natural sources that are replenished at a higher rate than they are consumed

1. relating to or derived from living matter
2. maintain (something) in its original or existing state
3. made of the layers of gases surrounding a planet or other celestial body
4. a place to dispose of refuse and other waste material by burying it and covering it over with soil
5. Contaminate
6. the production and discharge of something, especially gas or radiation
8. geographic area where plants, animals, and other organisms
11. Protect
13. relating to or determined by the sun
15. the natural home or environment of an animal, plant, or other organism