| Question | Answer |
| divergent | boundary where 2 plates are moving away from each other; associated with mid-ocean ridges |
| convergent | boundary where 2 plates are colliding; associated with deep-sea trenches, volcanoes, and mountains |
| transform | boundary where 2 plates are sliding past one another; associated with faults and earthquakes |
| Wegener | man who came up with the theory of continental drift |
| Hess | man given credit for the theory of plate tectonics |
| basalt | rock that covers most of the ocean floor |
| Pangaea | name of the supercontinent 200 million years ago |
| continental drift | theory stating the continents used to be joined in a single land mass and have since drifted to their current locations |
| subduction | one tectonic plate is being forced under another tectonic plate |
| mid-ocean ridge | chain of underwater mountains |
| deep-sea trench | long, narrow depression on the ocean floor; occurs at convergent boundaries |
| plate tectonics | theory that the Earth's crust is broken into plates which move in different directions at different speeds |
| lithosphere | strong, rigid layer of Earth including the uppermost mantle and overlying crust |
| asthenosphere | a weak plastic-like layer of the mantle situated below the lithosphere; convection currents happen here |
| seafllor spreading | theory stating that new crust is made at mid-ocean ridges and old crust is destroyed at deep-sea trenches |
| rift valley | long narrow depression that forms when continental crust separates at a divergent boundary |
| fault | fracture in the Earth's crust; transform boundary |
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Spanish 3
