The correct descriptions for the locations where Earth's volcanoes are formed are:
- They form in areas where Earth's crust is thin.
- They form along plate boundaries.
Volcanoes are commonly associated with regions where tectonic plates interact, such as at divergent boundaries (where plates move apart) and convergent boundaries (where one plate subducts beneath another). Additionally, areas where the crust is thinner can allow magma to easily ascend to the surface, leading to volcanic activity. While some volcanoes can occur in continental interiors (such as hotspots), the primary locations are indeed along plate boundaries and in regions with thinner crust.