Question

what idea best explains the different views of the north and the south about slavery

Answer 1

The north believed that slavery was wrong, and the south did not. 
Because of this view, the north relied on technological improvement in order to handle all of the operational process in each of their ecnomic sectors.
The southern part on the other hand, could only rely on slave labor for their plantation. Because of this, they felt their economic stability is threaten when Lincoln ordered the emancipation of the slaves

Answer 2

Property rights and the different cultures that existed in the north and south. The north was much more densely populated, with people living in cities and towns, and had little need for slaves. The south, on the other hand, was primarily rural, with tobacco, cotton, and other crops being widely farmed. The entire southern economy was dependent on slavery, and it was thus necessary to maintain the idea that slaves were property, not people.