What happens when two oceanic plates collide? what negative impacts for human populations can result from this type of action?

This is a 2017 topographic map of puerto rico in the united states, and i'm sorry that people there have suffered such a disaster. i want to ask, what do the yellow dots and areas represent on this graph? and the blue area and the little blue circle, and the little blue sign that looks like a signal tower, what do they stand for?

True or false. epeirogenic changes deform the crust.

Match the region in column 1 to the river in column 2