Plate Tectonics

3. -a current in a fluid that results from convection.
7. where plates slide sideways past each other.
9. -the sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate.
11. -one of the earliest ways geologists thought continents moved over time.
12. -the upper layer of the earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.
13. -an area on Earth over a mantle plume or an area under the rocky outer layer of Earth
15. -the process by which the North pole is transformed into a South pole and the South pole becomes a North pole.

1. -when two tectonic plates move away from each other
2. -All the earth
4. -the Earth's solid outer crust, the lithosphere, is separated into plates that move over the asthenosphere
5. -its lightest, most buoyant rock layer.
6. -the mostly solid bulk of Earth's interior.
8. -about 2,200 kilometers (1,367 miles) thick, is mostly composed of liquid iron and nickel.
10. -of a substance is its mass per unit volume.
14. -the rigid outer part of the earth, consisting of the crust and upper mantle.