Why do convergent oceanic plates subduct, but continental plates do not usually respond in this way?

(a) oceanic plates and continental plates are about the same density, so they mix with each other at boundaries.

(b) oceanic plates are made of dense rock; therefore they sink into the asthenosphere more readily. continental plates are made of lighter more buoyant rock.

(c) oceanic plates are made of very dense rock; therefore they rise into the asthenosphere more readily. continental plates are made of dense rock so they rise too.

(d) oceanic plates are made of less dense rock; therefore they rise into the asthenosphere more readily. continental plates are made denser rock.

D is the answer. Sand is part of the oceanic plates. Whenever a wave comes in, the wave sweeps in some sand over in the water. It will slowly roam around with the wave. If you get a rock from a continental plate and throw it into the water. The rock will go through and to the bottom in seconds.

(B) Oceanic plates are made of dense rock; therefore they sink into the asthenosphere more readily. continental plates are made of lighter more buoyant rock.

Explanation:

Continental crust is made from granite and is low density. Oceanic crust is made of higher density basaltic rock. So when low density continental plates converge, they rise to form a fold mountain. Dense oceanic plates however do not rise, they subduct into the asthenosphere.

that is wrong, its not thymus.