What was the chief economic connection between south and north?

Trade with food from the South and manufactured goods from the North.

Explanation:

This was the chief economic connection between the South and the North. During the Antebellum period, the North and the South engaged in trade in a very significant way. Each region traded in accordance to their chief industries and products. The South was particularly focused on agriculture, which meant that its trade focused on food. On the other hand, as the North had an advantage when it came to industry, it focused on manufactured goods.

the increased occurrence of polygamy

it further strained relations between the north and the south and convinced