Final answer:
Planters controlled the South's economic, social, and political life through their ownership of large plantations and reliance on enslaved labor.
Step-by-step explanation:
In the context of the Southern United States, the social class that controlled the region's economic, social, and political life was the Planters. Planters were wealthy landowners who owned large plantations and relied on enslaved labor to cultivate crops such as cotton or rice.