Answer:
the ability to fight defensively, rather than offensively
Explanation:
Union Army generals reexamined the offensive battle tactics developed during the Mexican-American War, with the goal of updating these tactics during the secession war. In this way, the Union had one more advantage in the conflict, since the army of the Confederates was flawed in defensive tactics. The Union Army had a greater number of soldiers, a substantial industry, an extensive railroad, and the ability to fight offensively.
