Final answer:
The American Civil War shaped modern America through political, economic, and social changes.
Step-by-step explanation:
The American Civil War was a significant event that had lasting effects on the United States. It shaped modern America by bringing about profound social, political, and economic changes. Politically, the war established the dominance of the federal government over the states. Economically, it undermined the South's plantation economy and strengthened the North's industrial economy. Socially, the war divided families and friends, and it led to the emancipation of enslaved blacks. Overall, the Civil War played a pivotal role in shaping the course of American history.