At the beginning of this unit you agreed or disagreed with statements about the movement of continents. Not all of the statements were true. Now that you have completed the unit, carefully think about each statement again then decide whether you agree or disagree with the statement based on what you have learned. How many of your responses changed?

1. The Earth's present-day continents were originally part of one gigantic supercontinent called Pangaea that existed over 200 million years ago. (Agree / Disagree)
   
   See "B1 - Continental Drift / The Fit of the Continents" for more information.
2. The theory that continents moved over time, known as continental drift, was immediately accepted by scientists when it was proposed in 1912. (Agree / Disagree)
   
   Wegener's theory of continental drift was not accepted by most scientists in Wegner's lifetime. The main stumbling block was that Wegener was not able to provide a suitable mechanism to explain why continents moved. See "B1 - Continental Drift / Climate Evidence" for more information.
3. Coal, which forms in swampy, tropical areas, has never been found in Antarctica. (Agree / Disagree)
   
   Large seams of coal have been found in Antarctica. This evidence is used to show that these areas must once have been large tropical swamps. See "B1 - Continental Drift / Climate Evidence" for more information.
4. A large oceanic mountain chain with a narrow valley down its center extends through the length of the entire Atlantic Ocean. (Agree / Disagree)
   
   See "B2 - Seafloor Spreading and Paleomagnetism / Seafloor Spreading" for more information.
5. The age of the ocean floor is about the same as the age of continents. (Agree / Disagree)
   
   The oldest oceanic crust is about 180 million years old, while the age of continental crust is measured in billions of years. See "B2 - Seafloor Spreading and Paleomagnetism / Seafloor Spreading" for more information.
6. The Earth's North and South magnetic poles have reversed themselves many times in the Earth's past. (Agree / Disagree)
   
   See "B2 - Seafloor Spreading and Paleomagnetism / Magnetic Reversal and the Curie Temperature" for more information.
7. The upper surface of the Earth is broken up into a number of large chunks of rigid material known as plates. (Agree / Disagree)
   
   See "B3 - The Theory of Plate Tectonics / The Theory of Plate Tectonics" for more information.
8. Continents move because of convection currents from deep within the Earth. (Agree / Disagree)
   
   See "B3 - The Theory of Plate Tectonics / What Drives Plate Motion?" for more information.