a volcano is a mountain or hill, typically conical, having a crater or vent through which lava, rock fragments, hot vapor, and gas are being or have been erupted from the earth's crust.
There are three main types of volcano - composite or strato,shield and dome. Composite volcanoes, sometimes known as strato volcanoes, are steep sided cones formed from layers of ash and [lava] flows. The eruptions from these volcanoes may be a pyroclastic flow rather than a flow of lava.
<span>A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gasses to escape from a magma chamber below the surface. Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle. There are young volcanoes and old volcanoes</span>
