4.) which of the following brought major improvement to the lives of african americans in the south?

The Fourteenth Amendment brought major improvements to the lives of African Americans in the South.

Explanation:

The 14th Amendment to the Constitution was adopted as a result of the Civil War. It contains the equal treatment clause, the right to an ordinary judicial process in the states and the basics of citizenship law. It was proposed for adoption on June 13, 1866 and ratified on July 28, 1868.

The constitutional amendment provides a broad definition of US citizenship. It promises equal protection for the laws of the United States, which are within the jurisdiction of different states, for all individuals (and not just citizens). The main concern of the authors was that equivalent protection be established regardless of race.  Therefore, this amendment granted citizenship and protection to all African Americans.