After the civil war, the federal government began to extend civil rights to african americans by
passing amendments to the constitution.
signing the emancipation proclamation.
paying reparations to them.
them move to the northern states.

passing amendments to the Constitution

Explanation:

The amendments was created as a form of 'adjustment' that was made to the initial draft of the constitutions. The purpose of these amendments is to address the issues that haven't been properly mentioned within the constitutions.

After the civil war, James Madison proposed the first 10 amendments for the constitutions. It consists of civil rights that is aimed to protect the citizens from the government's tyranny. They are eventually known as the Bill of rights.

i got 3,4 and 5 as an answer