It's B. The Columbian Exchange is just that, the exchange of goods, plants, people, etc. between Europe and the Americas
Answer:
The answer you are looking for is D, Traditions, I hope I helped. :D
Explanation:
The role that the Railroads played in the Southern Economy was that "They Shipped materials to Northern Markets" Their main goal was to ship crude materials.
D. The United States Constitution, it holds the basic laws of our nation, "land"
