Across
- 5. the solid layer of rock beneath soil
- 6. animal with no back bone
- 9. time divided in areas
- 12. the grinding away of rock by other rock
- 13. the preserved remains or traces of living things
- 16. the energy in an object
- 19. imaginary line through the middle of the earth
- 20. wide valley were a river flows
- 21. the force that opposes the motion
Down
- 1. one time in the past when continental glaciers covered large parts of the earth
- 2. a large mass of moving ice and snow on land
- 3. land form made of sediment deposited by a river
- 4. a land form with high elevation
- 7. donald trump
- 8. dark colored organic material in soil
- 10. wind erosion that removes surface materials
- 11. the energy to do work
- 14. lake a meander cut of from a river
- 15. soil organism that breaks down the remains of an organism
- 17. when a type of organism no longer exists any where on earth
- 18. a large change in soil formed by erosion