Answer:
Oceanic plate
Explanation:
In a convergent plate boundary, the denser plate undergoes subduction beneath the less denser plate. This zone is also known as the Beniof zone. The plates undergoes partial melting at great depths and the magma starts to rise up towards the over-riding plate, forming a volcano or chains of volcanoes.
The oceanic plate is comprised of denser mineral such as olivine, pyroxene and alkali feldpar. The density of oceanic plate is about 3 g/cm³, whereas the density of continental plate is 2.7 g/cm³.
Therefore, at a subduction zone, the downgoing plate is oceanic plate.
