Which of the following best explains how the ring of fire formed

¿cual es mas alta en baja california,la migracion o la inmigracion?

Which barrier to economic development is shown in the following examples?

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?