Explain why Wegner's use of shorelines to match continents in his reconstruction of Pangaea was criticized by other geoscientists and how that issue was subsequently resolved in Plate Tectonic Theory. 2- Explain briefly why a divergent plate boundary is also called a "constructive margin or boundary." 3- Briefly explain how density affects subduction. 4- Briefly explain how magnetic patterns on the seafloor support Plate Tectonic theory. 5- Briefly explain why the oceanic ridges are higher than the surrounding ocean basins.