Ch 2 Sec 3

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Across
  1. 2. 78% of earth's atmosphere is composed of this
  2. 3. number of planets that exist outside of our solar system
  3. 4. the part of the Earth that includes all life forms
  4. 6. solid crust of the planet
  5. 8. envelope of gases that surrounds Earth
  6. 9. holds atmosphere around a planet
Down
  1. 1. all of the surroundings of the earth
  2. 5. a group of different parts that work together to make a whole
  3. 7. all of the Earth's water