Across
- 2. large areas of flat land
- 5. dry dirt or pieces of soil or sand
- 8. low land between hills or mountains
- 10. notice something that is not clear or hidden
- 12. something that's necessary
- 13. machine sent into space to travel around the earth and collect data or communicate.
- 14. cause to happen or exist.
- 16. the layer of gasses around a planet
- 18. units to measure tilt
- 19. more important than everything else
Down
- 1. very large
- 3. progress in science or technology
- 4. asked yourself something
- 6. one part of a thing, situation, or problem
- 7. tools designed to do a job on their own
- 9. to provide
- 11. large areas of countryside
- 15. a person who studies the stars and planets
- 17. evidence