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

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

The answer would be:

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.

Her is more about your question:

In a convergent boundary plates collide or move towards each other. What happens between an oceanic plate and a continental plate that collides is that one would subduct beneath the other.

Oceanic plates are a lot thinner than continental plates and they are a lot more dense. Because continental plates are much thicker and less dense, they force the oceanic plates under. This process is called subduction.

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

"d.) carbon dioxide and hydrogen sulfide"