What product played a critical role in the development of the economy in the south?

Cotton played a critical role in the development of the economy in the South, particularly during the 19th century. The invention of the cotton gin made cotton production more efficient, leading to a boom in the cotton industry. This not only increased the demand for slave labor but also established the South as a dominant player in the global cotton market, shaping its economic and social structures. The reliance on cotton contributed significantly to the region's wealth and was a major factor leading up to the Civil War.