What is one characteristic of a volcano?

A defining characteristic of a volcano is its ability to release magma to the surface, which is observed during eruptions. This process involves the ascent of molten rock from beneath the Earth's crust, where it may accumulate in magma chambers before erupting through vents to form lava flows, ash clouds, and other volcanic products. This release of magma is crucial to the formation of new landforms and contributes to the geological processes that shape the Earth's surface.

While metamorphic rocks are formed under high pressure and temperature conditions and sedimentary layers accumulate from the deposition of materials, these processes are not unique to or typically associated with volcanic activity. Additionally, while some volcanoes can be found along fault lines due to tectonic activity, it is not a requirement for all volcanoes. The hallmark of a volcano is primarily its capability to erupt and expel magma.