Final answer:
The invention that led to an increase in the demand for slaves was the cotton gin.
Step-by-step explanation:
The invention that led to an increase in the demand for slaves was the cotton gin. The cotton gin was invented by Eli Whitney in 1794, and it revolutionized the cotton industry by making it easier and faster to separate cotton fibers from the seeds. As a result, cotton production boomed, leading to increased demand for slave labor to work on cotton plantations.
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