Final answer:
The North financed its Civil War efforts mainly by selling war bonds, while the South did so by printing money.
Step-by-step explanation:
The North financed its war effort primarily by selling war bonds. This was a common method for governments to raise money for military campaigns, as it allowed them to borrow money from citizens by promising to pay it back with interest at a later date. Contrary to the North's approach, the South relied more heavily on printing money to finance its war efforts, which ultimately led to inflation and other economic issues.