What causes the wavelength of a particular beam of light change?

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?

Which of the following is a characteristic differentiating tropical and temperate rainforests? a. the location b. the types of trees c. the average temperature d. all of the answers are correct

There is a lot of volcanic activity in southeast asia because much of the area lies on