Final answer:
The most impactful type of change on Southern life was social change, specifically the founding of the Ku Klux Klan and the rise of racial tensions.
Step-by-step explanation:
The Civil War and Reconstruction had significant impacts on Southern life in terms of political, social, and economic changes. While each type of change played a role, the most impactful on Southern life was social change. The founding of the Ku Klux Klan (KKK) and the rise of racial tensions and violence affected all aspects of daily life and created a climate of fear and oppression for African Americans.