Advancing warm air that displaces cold air

What was the great rift valley formed by

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?

Islam and the arabic language spread throughout north africa in the 600s primarily through a. african traders b. american colonists c. european explorers d. middle eastern armies select the best answer from the choices provided