Final answer:
The cotton gin improved the profitability of plantations and increased the dependence on slave labor in the South.
Step-by-step explanation:
The main impact of Eli Whitney's cotton gin on the South was that it improved the profitability of plantations, which made cotton the South's main crop. The cotton gin was a machine that could quickly and effectively separate the seeds from the cotton fibers, making cotton production faster and more efficient. This led to an increase in demand for cotton and an expansion of cotton growing in the South. However, it also increased the dependence on slave labor as the demand for cotton increased.
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