Across
- 2. the most abundant greenhouse gas
- 3. made up of nitrogen and oxygen
- 7. Doesn't react easily with other gases
- 8. 21 percent of air
- 9. o3
- 11. heat
- 13. 1 carbon and 2 oxygen atoms
- 14. trap thermal energy
Down
- 1. The amount of the element stays constant
- 3. layer of gases that surrounds planets or stars
- 4. the process of plants turning light into food
- 5. cattle process it in their digestive process
- 6. 78 percent of air is this gas
- 10. changes with a change in the environment
- 12. weight