Across
- 1. the planet we studied in this unit
- 5. a feature that forms on the surface of a planet, such as a mountain, channel, or sand dune
- 8. all the liquid water and ice on a planet
- 9. the mixture of gases surrounding a planet
- 11. having the conditions necessary to support life
Down
- 2. a set of interacting parts forming a complex whole
- 3. all the living things on a planet
- 4. this formed the channel on mars
- 6. the solid part of a rocky planet
- 7. a long, narrow groove that forms where water, lava, or other liquid flows
- 10. an object, diagram, or computer program that helps us understand something by making it simpler or easier to see