B. Two continental plates colliding
The correct answer for the question that is being presented above is this one: "B. a decrease in pressure." At divergent plate boundaries in the ocean, magma rises and melts because of<span> a decrease in pressure. The magma rises and melts as the divergent plate boundaries in the ocean decreased in pressure.</span>
Answer:
their closer together while still the same form
Explanation:
they have moved closer together causing the land to collide more with the other side making the river smaller. It keeps the same shape just combined tighter.