<span>the ability of a state or territory to decide for themselves whether or not to allow slavery </span>
The land that the United States gain from the war of 1812 was CANADA
The South relied heavily on steamboats for transportation of supplies and troops. They absolutely needed the Mississippi River to be effective in anyway during the war. The North also used it for transporting, but they had railroads. They were mostly concerned with keeping the South from using it.
The answer to the question is c) Check