Group C

1. Crust The part of the Earth's lithosphere that surfaces in the ocean basins, primarily composed of mafic rocks or sima. It is rich in iron or magnesium.
3. Said to occur when continental plates slide and grind against each other. the relative motion of such plates is horizontal in either sinistral or dextral direction.
4. Where 2 plates are moving away from each other and new crust is forming from magma that rises to the Earth's surface between the two plates.
5. Tectonics A theory in which the lithosphere is divided into crustal plates, each of which moves on the plastic asthenosphere more or less independently to collide with, slide under or move past adjacent plates.

2. When 2 plates are moving toward each other. 2 plates equal - density, push up against each other, forming mountain chain. 2 plates unequal - 1 plate sinks beneath the other in a subduction zone.