What year did Panama obtain control over the canal from the United States?

What does a movement along the demand curve show

What are the similarities and differences in the way geologists and biologists approximate the age of the earth? justify your response in two or more complete sentences.

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?