What advantages did the south have in winning the civil war?

They didn't win. You mean what were their advantages, relative to the North?

1. Leaders - some of the best officers of the US Army had quit to join the Confederates.

2. Soldierlike people - the Confederates were the sort of men who actively relished a fight.

3. Advantage in Cavalry - most young men were used to the riding and shooting way of life.

4. Home-ground factor - nearly all the fighting was on ground unfamiliar to the enemy.

5. Powerful mission - strong incentive to defend the homeland against the invader.