Across
- 4. mechanical waves that travel through the rock layers of the Earth
- 7. the numeric age of a layer of rocks or fossils
- 11. requiring the presence of air
- 12. any organism or process which can or must exist without free oxygen
- 14. the numeric age of a layer of rocks or fossils
- 15. a rock that falls to Earth from space
- 17. a stable, broad, horizontal rock formation of the earth's crust
- 18. part of the recycling process in plate tectonics
- 19. living things within an ecosystem
Down
- 1. the study of magnetism in ancient rocks
- 2. the study of the forms and features of land surfaces
- 3. a process that lowers or tears down the surface features of the Earth
- 5. the process of transferring heat through air or liquid currents
- 6. the time required for a quantity to reduce to half its initial value
- 8. Atoms with the same number of protons but different numbers of neutrons
- 9. estimate whether an object is younger or older than other things found at the sit
- 10. gigantic pieces of the Earth's crust and uppermost mantle
- 11. Not associated with or derived from living organisms
- 13. evolution that occurs among interdependent species as a result of specific interactions
- 16. the study of earthquakes and seismic waves