The area of high population density that stretches from boston to washington,
d. c. , is a megalopolis.
a. true
b. false

The meseta in spain is a a. navigable river b. castle c. coastal plain d.plateau

If a volcano’s magma is high in silica, the volcano will probably a. erupt quietly. b. remain dormant. c. erupt explosively. d. produce dark-colored lava.

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?