Balance in our Ecosystem

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Across
  1. 3. A change in the natural conditions of the Earth
  2. 8. A layer of gas surrounding the atmosphere
  3. 9. Life needs this to survive
  4. 10. This is responsible for almost 75% of oxygen on Earth
  5. 12. There are many trees here
  6. 13. Animal Kingdom
Down
  1. 1. Orangutans, rhinoceros, and blue whales are all _________ species
  2. 2. Plant life
  3. 4. Its usually cold up in the _______
  4. 5. Earth would not be habitable without it
  5. 6. Only planet in the solar system that has life
  6. 7. Living underwater rocks
  7. 11. The primary element in all life