What are some reasons to consider San Francisco and Hong Kong as part of some region

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?

Formidable obstacles of climate, terrain, and distance hinder exploitation of natural resources in russia. true false

What is the main source of phosphorus?