Answer:
When magma comes to the surface a volcano may form.
Step-by-step explanation:
The magma is a very hot viscous material. It forms in the mantle, where the temperatures are very high and the rock gest is melted, but also mixed with gasses. Even though magma forms in the mantle, it is constantly present on the surface and this is because of the high pressure on which the crust is exposed and eventually cracks.
When magma comes toward the surface, it gradually lifts up the surrounding area, or rather the crust, in what looks like a cone-shaped mountain. When the crust can not expand further, it cracks, and as it does magma comes out on the surface. This is how a volcano forms. The volcanoes can be found in a lot of places around the world, but the vast majority of them are found along the plate boundaries, with a much smaller number being located over the plates, and those are formed by hot spots.