Across
- 1. Life requires this liquid to be available.
- 2. This molecule of life requires a temperature range that is not too hot or not too cold.
- 7. Earth and Mars have very similar chemical ________ (ingredients).
- 8. Earth's atmosphere is a great insulator for temperatures, provides certain nutrients, and even provides a magnetic and chemical ______ for life.
- 10. Comparing Earth to this neighbor.
- 11. Our home planet.
- 13. Earth's average surface ______ is 15 degrees Celsius.
- 15. Many processes exist on Earth to ____ nutrients such as plate tectonics.
Down
- 1. Earth's water exists in all three states creating this.
- 3. This provides important protection and a source of biochemicals.
- 4. Water on mars almost always exists in this state.
- 5. Mars in on the edge of this zone.
- 6. Mars' atmosphere is too thin to insulate or protect the surface and is mostly made of this gas.
- 9. They make almost all of the food chains on Earth possible.
- 12. Mars's average surface temperature is far below _______.
- 14. Organisms need light, heat, or chemicals to gain this to live.