The correct answer to this open question is the following.
Although you do not specify, we assume that you are talking about the historical time of the American Civil War in 1861. If that is the case, then the side that had the advantage, if war were to break out between the two sides would be the North.
The reason why is that the northern states developed a strong industry that allowed the federal government to provide better weapons and supplies for the Union army. These industries had the technologies and machines in the fabric to mass-produce goods that were used in the Civil War.
On teh other hand, the southern states did not have industry. They heavily depended on slavery. Landlords owned slaves that worked for long hours to produce the crops that had to be traded and exported to England. So the economy of the Sout relied on slaves and agriculture.