When divergent boundary occurs on land it forms

Match the following terms and definitions a region in arkansas defined by the arkansas river in the western part of the state answer 1 a thoroughly dissected area with steep valley walls and narrow floors answer 2 a geographical region of a country or state answer 3 the friendly and generous reception and entertainment of guests, visitors, or strangers answer 4 the branch of knowledge concerned with the production, consumption, and transfer of wealth answer 5 statistical data relating to the population and particular groups within it answer 6 a mountain range in west central arkansas and southeastern oklahoma answer 7 travel for pleasure or business; also the theory and practice of touring, the business of attracting, accommodating, and entertaining tourists, and the business of operating tours answer 8 answer all parts of the question.

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?

Based on what you know about speed of light and sound, which come/comes first in a thunderstorm