| A | B |
|---|
| Ocean Floor Spreading | Lava erupting from the midocean ridge creates new ocean floor causing the continents drift apart |
| Theory of Continental Drift | The theory that stated that continents were once joined together and have since drifted apart |
| Midocean Ridge | large systems of underwater mountains that have deep crack running through their center where new ocean floor is created |
| Pangaea | 200 million years ago the Earth had a single giant landmass that broke up into large pieces |
| Transform Fault | A fault that runs across a midocean ridge |
| Trench | V shaped valleys that lie along the bottom of the ocean where old ocean floor is subducted |
| Subduction | the process in which crust plunges back into the Earth |
| Fossil | the preserved remains or evidence of ancient organisms |
| Alfred Wegener | A German scientist who suggested that continents had once been joined together and had since moved apart |
| Glossopteris | An extinct plant found in fossils in the areas of Southern Africa, Australia, India, and Antarctica |
| Theory of Plate Tectonics | Theory that links together the ideas of continental drift and ocean floor spreading and explains how the Earth has changed over time |
| Convergent Boundary | plate boundary at which plates push together |
| Divergent Boundary | plate boundary where plates move apart |
| Hypothesis | proposed solution to a scientific problem |
| Theory | logical explanation for events that occur in nature |
| Law | scientific theory that has survived many tests and is generally accepted as true |
| Evidence | that which tends to prove or disprove something: ground for belief, proof |
