Answer:
The correct answer is segregation was not the same as discrimination.
Although on Edge it is, "segregation did not constitute discrimination."
It is worded a little different
Answer:
Because they needed more supplies to survive
People in the south used slaves because their economy was focussed on things like cash crops (tobacco, cotton, etc.) These crops required a lot of work so farmers and plantation owners could not do it by themselves. So by using enslave persons they could harvest more crops, sell more, make more money, and in return boost the southern economy.