Across
- 3. a gas that humans and animals need to live
- 7. transfer of thermal energy
- 8. earths atmosphere at a particular time or place
- 10. evaporation from leaves of plants
- 12. forms about 78 percent of the earths atmosphere
Down
- 1. protects us from ultraviolet radiation from the sun
- 2. material that is harmful to humans
- 4. rain sleet snow hail
- 5. layer of gas that surrounds the earth
- 6. gas to liquid
- 9. smoke and fog
- 11. quality the amount of pollution in the air