Answer:
Cotton gin.
Explanation:
The cotton gin was a machine that separates the cotton from their seed in an easy way. They improve the separation made by hand that was made before the invention of this.
The invention of it contributes to the growth of slaves in the South of the United States because in that region is where the farmers began to growth Cotton massively and therefore they needed more workers. The plantations grew until they became the larger sector of the southern economy.
I hope this answer helps you.
