Earth Day

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Across
  1. 2. the envelope of gases surrounding the earth or another planet.
  2. 4. decayed organic material used as a plant fertilizer
  3. 6. protects (something, especially an environmentally or culturally important place or thing) from harm or destruction.
  4. 7. maintain (something) in its original or existing state.
  5. 8. trash, such as paper, cans, and bottles, that is left lying in an open or public place
  6. 9. the branch of biology that deals with the relations of organisms to one another and to their physical surroundings.
Down
  1. 1. relating to or derived from living matter.
  2. 3. the sun's rays as a source of energy from which power for domestic or industrial use may be generated.
  3. 5. 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).
  4. 7. contaminate (water, air, or a place) with harmful or poisonous substances.