What two countries have been especially prominent destinations for economic migrants?

The two countries are United States and Canada.  Most settlers transfer for economic reasons. Individuals think about relocating from places that have few job openings and they settle to places where jobs are most expected to be available. And these two countries are areas that has appreciated natural resources which attracts people especially engineers, factory workers, technicians, scientists and so on that is why people are going here.

they made rome the dominant power in the mediterranean.