What volcanic feature forms as a direct result of subduction?

When tectonic plates converge at a subduction zone, one plate is forced beneath another into the mantle, a process that leads to significant geological activity. This subducting plate melts and contributes to the formation of magma, which rises to the surface, resulting in volcanic activity.

Island arcs are specifically formed in this context as chains of volcanic islands that develop parallel to the trench where the subduction occurs. As the oceanic plate sinks into the mantle and generates magma, it leads to the creation of these islands, often found in a curved formation. Thus, the formation of island arcs is a direct consequence of the processes related to subduction zones.

The other geological features listed in the choices—mid-ocean ridges, plateaus, and rift valleys—do not arise from subduction. Instead, mid-ocean ridges are formed at divergent boundaries where tectonic plates are moving apart, while plateaus may form due to uplift from volcanic activity or sedimentation but are not a direct result of subduction. Rift valleys occur at divergent boundaries as well, where tectonic plates are pulling apart rather than converging.