How have countries in East Asia attempted to address their overpopulation issue? in one paragraph please!!

In the diagram below, ab and bc are tangent to o. what is the measure of

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 two nations are doing the most to combat their environmental issues?