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.
There were several nations who sought to claim the territory such as the Americans, British, French, and Spanish. John Quincy Adams resolved this through the Treaty of 1818 where the border of the United States and Canada was established at the 49th Parallel.
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U.N. resolution condemning the use of atomic weapons