Across
- 4. mental processes, such as thinking, learning, and problem solving
- 6. causing illness or death when eaten
- 9. our planet's layer of molten rock
- 10. a warm-blooded animal that has a back-bone, has fur or hair, and nurses its young
- 12. working because of machines or machinery
- 14. the science that studies earthquakes
- 15. our planet's outermost layer
- 17. a scientist who studies how living and nonliving things interact with one another
- 18. the area in which an animal or plant lives
- 19. the temperature at which a liquid turns to a solid
- 20. a device designed to replace a missing or injured body part
- 21. a piece of plastic smaller than 5 millimeters in length
Down
- 1. when materials harm the environment
- 2. a visual display that uses quick facts and images to show information or data
- 3. animals that eat dead creatures and scraps of food lying around
- 5. a body movement that communicates an idea or a feeling
- 7. a chemical that breaks down oil
- 8. a scientist who studies Earth
- 11. a device to carry electricity to a nonmetal sruface
- 13. a stream of water moving within a body of water
- 16. giant slabs of rock in Earth's crust