3. what do you think is the average recurrence interval of the kind of object that collided with the colorado plateau in arizona, which created meteor crater, if it was about 50 meters in diameter?

a. in the hundreds of years

b. in the thousands of years

c. in the tens of millions of years

d. in the hundreds of millions of years

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?