What were some differences between the north and south that increased tensions between the two regions

First of all, the North and the South had big production differences.

Since the Northern states were by water they could build more factories than the south. This caused a much more biggest boom of industry than the South.

The south relied on agriculture more. The climate there had enough rain and rich soil to grow crops hence it caused plantation owners and farmers to use slaves more. Because of this, the South advocated for slaves more as they needed them to product food and get money.

The north also had more abolitionists since the north relied on machinery so they didn't need slaves and thought it was immoral.

This argued the South as they saw it as the North trying to affect their businesses. Furthermore, the South saw slavery as a necessary system since they claimed that black people didn't know any better and slaves were much better taken care of by their masters as they were feed and clothes (though this is obviously not true)

So in summary:
*climate and land differences=slavery vs. machinery
*South:Pro slavery vs. North:anti slavery
I hoped this helped you a little bit