Why does the economy of the northeast tend more towards business and trade than farming?

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?

Witch of the following types of boundaries is most likely to result in a subduction zone

Iii-eneral sciencewhich of these is the best explanation of how a smooth round stone became smooth? a continuous freezing and thawingbvolcanic actioncit fell off the side of a cliffdit was in a stream for a long time.