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1. A volcano is a mountain that forms when layers of lava and volcanic ash erupt and build up. 2. Between the molten iron core and the thin crust at the surface deep inside the earth there is a solid body of rock called the mantle. When rock from the mantle melts, moves to the surface through the crust, and releases pent-up gases, volcanoes erupt. 3. Magma rises when extremely high temperatures and pressure cause the rock to melt and become liquid rock or magma. When a large body of magma has formed, it rises through the denser rock layers towards Earths surface. 4. The difference between magma and lava is that magma is the hot molten rock inside of a volcano and lava is the molten rock that has reached the earth’s surface. 5. Volcanoes can occur at divergent plate boundaries, at the convergent plate boundaries, and at locations not at plate boundaries called h