Despite different methods of ranking cities, which cities tend to typically prove to be “dominant” in the urban hierarchy? Which regions primarily have high numbers of cities in the higher rankings of the urban hierarchy

Why are shark population in decline worldwide?

Is a state government creates a new tax to fund schools a example of checks and balances

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?