Final answer:
True, the federal government extended civil rights to African Americans after the Civil War by passing the Thirteenth, Fourteenth, and Fifteenth Amendments, as well as the Civil Rights Act of 1866.
Step-by-step explanation:
The statement that after the Civil War, the federal government began to extend civil rights to African Americans by passing amendments to the Constitution is true. Following the Civil War, Congress passed the Thirteenth Amendment, which abolished slavery. To combat the Black codes and protect the rights of African Americans, Congress also enacted the Civil Rights Act of 1866, and later, the Fourteenth and Fifteenth Amendments were ratified, which defined citizenship, guaranteed equal protection under the law, and secured voting rights for Black males, respectively. Nevertheless, despite these legal protections, the implementation of Jim Crow laws at the end of the 19th century severely limited those rights through segregation and disenfranchisement.