Across
- 2. The layer of rock that forms Earth’s outer layer.
- 6. The study of planet Earth
- 7. The material that forms Earth’s hard surface.
Down
- 1. The layer of hot; solid material between the crust and core.
- 3. A deep valley that forms where two plates move apart.
- 4. A trace of an ancient organism that has been preserved in rock.
- 5. A dense sphere of solid iron and nickel in the center of Earth.