The Mexican American War heightened tensions over slavery in that there were many disagreements over whether the new territories won from Mexico should be free or slave territories. The Wilmot Proviso, created to solve the problem, ended up slitting parties on regional areas.
Good luck :)
A disagreement between two states, would be settled by, The Legislature of the Federal Government.
I think the industrial cuz when the extend the land everyone will capture the land and they should bring slaves and do farming but the farming can make the economy strong