What is an enclosed body of coastal water that is a mixture of salt water and freshwater called?

Hey, i was what is consisted in a sustainable city? like what unique designs they have, etc. for answering ; )

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?

Countries that have a traditional economy often develop at a slower pace than countries with a free market economy. true or false