Final answer:
Both the Confederacy and the Union had military advantages at the onset of the Civil War. The Confederacy's defensive position, familiar terrain, and military leadership were strengths, while the Union's large population, industrial capacity, and logistical advantages from its railroad network and food supply countered these strengths.
Step-by-step explanation:
At the onset of the Civil War, both the Confederacy and the Union had distinct military advantages. The Confederates had the advantage of fighting a defensive war within familiar territory, with shorter supply lines, and they could rely on local support.
On the other hand, the Union held significant advantages as well. They had a larger population, more abundant resources, and were more industrially advanced with an extensive railroad network, which provided superior logistics and mobilization capabilities.