Answer:
South
Step-by-step explanation:
As America was being colonialized, the South was more suitable for cash crops, which were grown on plantations with slaves. As the North industrialized, the South didn't need to because they had slaves, but the North kept pushing the South to abolish slavery, pressuring it to do something (unsuccessfully advocate in the government) or secede from the Union. If slavery was abolished, the South would have lost its most valuable labour force and economic progress.