It was the idea of "Manifest Destiny" that was the belief that it was God’s plan for the United States to own most or all of North America, since people thought the US was "destined" to occupy all the territory from the Atlantic to the Pacific.
As part of being readmitted to the Union, states had to ratify the new amendments to the Constitution. The Union did a lot to help the South during the Reconstruction. They rebuilt roads, got farms running again, and built schools for poor and black children. Eventually the economy in the South began to recover.
Definately <em><u>B. The Automobile</u></em>