Across
- 3. All land masses on Earth.
- 5. When greenhouse gases warm the Earth.
- 7. A process where nitrogen cycles through non-living and living environments.
- 9. Preserved remains of organisms that are now dead.
- 11. All liquid water on the suface of the Earth.
- 12. Places on Earth where the soil or rock layer's temperature never goes higher than freezing point.
- 14. Bacteria that absorbs nitrogen from air and then converts it to ammonia then nitrates.
- 17. A type of fuel that contains preserved plant and animal's carbon from millions of years ago.
- 18. When the Earth's climate changes
Down
- 1. Layers of gas that surround the Earth or a planet.
- 2. When the world's temperature average starts to increase.
- 4. The state of the atmosphere at a particular time or place.
- 6. When human activity causes an increase in the natural greenhouse effect.
- 8. When the ocean currents show a circular pattern in the major ocean basins.
- 10. Amount of time between glaciations.
- 13. The movement of Ocean water on a continuous basis.
- 15. All living things on Earth.
- 16. When carbon is recycled through water, soil and living things