1. What characteristics define the lithosphere and the asthenosphere, and how do these layers relate to each other relative to plates, plate boundaries and plate motions?
2. Why was the continental drift hypothesis just a hypothesis rather than scientific theory?
3. How does melting occur and igneous rock form at a divergent plate boundary (like the Mid-Atlantic Ridge)?
4. What is the tectonic setting of the Cascade volcanoes? The description of the tectonic setting needs to include the plate names, types of the lithosphere at the boundary, and specific boundary type responsible for forming the volcanoes. Also, be sure to explain how and where melting occurs that generates the magma that fuels the volcanoes.