What separated the tidewater and the piedmont? the hudson river the chesapeake bay the fall line

The fall line separated the tidewater and the Piedmont. The correct answer will be the fall line. 

Aregion is an area of land that has common features. these features can be natural, such as climate or landscape. they can also be artificial, such as language or religion. the xinjiang uyghur autonomous region, above, is an area of china inhabited by uyghurs, a muslim group with ethnic ties to turkish people.

Answer they are produced by collision of tectonic plates;