Why did one region need slavery? Why did the other one not need it?

Some regions of the United States had the need to resort to slave labor to finance their economic production, which was eminently agricultural and livestock and, therefore, required the use of greater numbers of people for the exploitation of resources. These regions were mainly those located towards the south of the country, in states such as Florida, Georgia, Alabama, etc.

Others, on the other hand, turned to industrial production as the main source of economic production. Thus, they did not require the use of so much labor, so they did not use slave labor to maximize their production.

51% were unhappy, i think .   ; )

answer; reactive is your answer; good luck