Why was the United States torn apart by the Civil War and
how did the aftermath, along
with new amendments
to the Constitution,
change the nation?

The Civil War was a war that was fought to control the government of the North, the Unions, and the south, the Confederate. The confederate wanted to govern themselves in fear that the newly appointed president, Lincoln, would discontinue chattel slavery, so the south secede from The United States of America which formed the country apart. The aftermath changed the nation by making slavery illegal while also giving newly freed slaves some rights. The aftermath also created a stronger central government.

Hopes this helps.