Earth day crossword puzzle

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Across
  1. 3. Shields earth from the sun's ultraviolet rays
  2. 10. A branch of biology that deals with organisms and their surroundings
  3. 11. Related or meaning the sun
  4. 12. An environment for animals or humans
  5. 15. A place where large amounts of organisms live
  6. 17. Trash
  7. 18. A product of gas or radiation
  8. 19. To protect something so it lasts
  9. 20. Something that can be used more than once
Down
  1. 1. Disposing of waste and trash
  2. 2. Rotting organic material to be used as plant fertilizer
  3. 4. Surroundings that living creatures and grow and sustain themselves in
  4. 5. A species of animal that has been wiped out
  5. 6. To reuse an item and is better value than what it once was
  6. 7. turning trash into reusable material
  7. 8. Contaminated air, water or, a place
  8. 9. To be maintained
  9. 13. To keep something as it is
  10. 14. An envelope of gasses that encircle the planet
  11. 16. Something that lives and can decompose