Noor's crossword

4. no longer in existence
5. a volcano that is erupting
6. outer layer of the Earth
7. the plates sliding sideways past each other
9. a single landmass
10. periods of thousands, millions, and billions, of years referred other scientists who study the earths history
12. outer part of the earth
14. a boundaries between tectonic plates that are moving towards each other
17. a scientist who uses fossil evidence to study life in prehistoric times
18. the size of a diagram or model in proportion to the actual size of a object
19. the middle part of the earth
20. a large natural elevation of the earth's surface

1. a volcano that has not erupted for at least 10,000 years, but scientists think it may erupt again
2. an area where one tectonic plate is forced downward
3. a boundary between tectonic plates that are moving away from each other
8. part of the earth between the core and the the crust
11. a theory that the contents were attached together in the past, and have been falling apart ever since
13. the upper layer of the earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection in thought to occur
15. a sudden shaking of the ground
16. volcano built up of ash or lava