Convergent Boundary: The boundaries between tectonic plates that are colliding.
Divergent Boundary: The boundary between two tectonic plates that are moving away from each other.
Transform Boundary: The boundary between tectonic plates that are sliding past each other horizontally.
Convection Current: A current in a fluid that results from convection.
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Oceanic Crust: The relatively thin part of the earth's crust that underlies the ocean basin. it is geologically young compared with the continental crust and consists of basaltic rock overlain by sediments.
Continental Crust: The relatively thick part of the earth's crust that forms the large landmasses. it is generally older and more complex than the oceanic crust.