The correct comparison is:
Both mountains and volcanoes have the same outward appearance. However, mountains are formed by movements of tectonic plates, whereas volcanoes are formed from pockets of magma that rise up during eruptions.
This response accurately distinguishes between the formation processes of mountains and volcanoes while acknowledging a similarity in their appearance. Mountains are typically formed through tectonic activity, such as the collision of tectonic plates, while volcanoes are formed from magma that erupts from below the Earth's surface.