Final answer:
After the Civil War, the federal government extended civil rights to African Americans through constitutional amendments.
Step-by-step explanation:
After the Civil War, the federal government began to extend civil rights to African Americans by passing amendments to the Constitution. These amendments, such as the 13th Amendment which abolished slavery and the 14th Amendment which granted citizenship and equal protection under the law, were crucial in ensuring civil rights for African Americans.
Learn more about African American civil rights after the Civil War