Subduction of tectonic plates causes the formation of , which are the deepest areas on the planet.

Subduction of tectonic plates causes the formation of  Volcanoes, which are the deepest areas on the planet.

Explanation:

Subduction is refers to as a geographical process that occurs at the convergent boundaries of the tectonic plates.In this process one plate moves under the other plate and then these plates sinks because of gravitational energy of the mantel.The regions where this process take place is know as the  subduction zones.

Tectonic Plates refers to a scientific theory that describes the movement of several large and small plates under the lithosphere of the earth.

Thus the process of subduction of tectonic plates causes the formation of  Volcanoes, which are the deepest areas on the planet.