What was the major economic system in the Southern U.S. before the Civil War?

The major economic system in the Southern U.S. before the Civil War was plantation agriculture reliant on slave labor. This economic model was characterized by large plantations that produced cash crops such as cotton, tobacco, and sugar, which were labor-intensive and required a significant workforce to cultivate and harvest. The reliance on enslaved African Americans was central to this system, as they provided the labor necessary for these plantations to thrive and generate substantial profits.

The growth of the plantation economy contributed to the region's social and political structures, as well as its cultural norms, which were deeply intertwined with the institution of slavery. This reliance on a slave-based economy created a distinct Southern identity and led to significant tensions with the industrialized North. Plantations needed not just the labor force but also the complex social systems that supported slavery economically, politically, and culturally.

Other options represent different economic activities but do not accurately capture the prevailing economic system of the South during this period. Industrial manufacturing was primarily concentrated in the North, small-scale farming without slaves was less prevalent due to the dominance of large plantations, and barter trading was not significant enough to define the economic landscape.