Across
- 4. greenhouse gas excreted by livestock
- 6. 78% of air
- 7. a trace gas
- 11. coldest atmospheric layer
- 12. most abundant greenhouse gas
- 16. 21% of air
- 17. natural source of oxygen
- 19. covers most of the Earth's surface and absorbs atmospheric gases
- 21. the atmosphere traps heat
- 24. contains ozone
- 25. gases that allow the greenhouse effect to occur
Down
- 1. result of melting ice caps
- 2. evaporated water
- 3. ozone depleting substance
- 5. closest atmospheric layer to Earth
- 8. another result of global warming
- 9. release substances like sulfur, ammonia, and carbon dioxide when they erupt
- 10. result of humans changing the greenhouse effect
- 13. absorbs UV rays
- 14. mini-layer contained in the thermosphere
- 15. about 1% of air
- 18. another greenhouse gas
- 20. result of global warming
- 22. farthest layer from Earth surface
- 23. gases found in trace amounts in air