what type of plate is plate a what about plate b why do you say so

Plate A is an oceanic plate and Plate B is a continental plate.

Why Plate A is oceanic

• It is shown beneath the ocean surface in the cross‑section diagrams used in textbooks and homework help sites for this exact question.

• It is the plate that subducts (dives down) beneath the other plate at the convergent boundary, which is typical behavior of denser, thinner oceanic crust.

• A deep‑sea trench forms where Plate A bends downward, another hallmark of an oceanic plate being forced under a lighter plate.

A simple way to picture it: Plate A is the “heavier” seafloor slab sliding underneath.

Why Plate B is continental

• Plate B is drawn as the thicker, higher-standing landmass with mountains forming on top, which matches the structure of continental crust.

• Because continental crust is less dense, it does not easily sink; instead it overrides the oceanic plate while the edge crumples and uplifts into mountain ranges.

• The subduction of Plate A beneath Plate B is the classic oceanic–continental convergent boundary used in school examples and solutions to this question.

So, we say:

• Plate A: oceanic plate (denser, subducting, under the ocean).

• Plate B: continental plate (less dense, forms mountains, represents landmass).

Information gathered from public forums or data available on the internet and portrayed here.