Earth Day

3. the surroundings or conditions in which a person, animal, or plant lives or operates
5. able to be maintained at a certain rate or level.
7. a mixture of gases that surrounds the Earth.
9. decayed organic material used as a plant fertilizer
11. the natural home or environment of an animal, plant, or other organism.
12. maintain (something) in its original or existing state
15. contaminate (water, air, or a place) with harmful or poisonous substances.
16. protect (something, especially an environmentally or culturally important place or thing) from harm or destruction.
17. a geographic area where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life.

1. (of a species, family, or other group of animals or plants) having no living members; no longer in existence
2. (of a contract, agreement, etc.) capable of being renewed
4. relating to or derived from living matter.
6. the production and discharge of something, especially gas or radiation.
8. convert (waste) into reusable material.
10. a place to dispose of refuse and other waste material by burying it and covering it over with soil, especially as a method of filling in or extending usable land.
13. trash, such as paper, cans, and bottles, that is left lying in an open or public place.
14. reuse (discarded objects or material) in such a way as to create a product of higher quality or value than the original
18. a colorless unstable toxic gas with a pungent odor and powerful oxidizing properties, formed from oxygen by electrical discharges or ultraviolet light. It differs from normal oxygen (O2) in having three atoms in its molecule (O3).
19. relating to or determined by the sun.
20. the branch of biology that deals with the relations of organisms to one another and to their physical surroundings.