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