The downward part of convection current causes a sinking force that a) pulls tectonic plates toward one another b) move play apart from one another c) lifts and splits the lithosphere d) create a divergent boundary

Option (A)

Explanation:

The convection current generates in the mantle, that forms when the hot magma being less denser rises up towards the upper portion of the mantle. This uprising magma force the plates to move over the asthenosphere layer.

The downward part of the convection current causes a force that allows the plates to sink. This sinking force leads to the formation of the convergent plate boundary, where two plates collide with one another and the denser plate gets subducted below the less denser plate. This type of plate boundary is often marked by the presence of a trench and volcanic as well as island arcs are formed.

Thus, the correct answer is option (A).

it cools slower in the earth meaning the crystals have more time to form than lava on the surface