What was the main reason northern states opposed slavery?

It was an unfair business advantage, is the right answer.

Explanation:

The antislavery movement that began in the North during the 1830's is more popularly known as the Abolitionism. According to the Abolitionists, slavery was unfair and thus it should be eliminated. The main reason why the Northern opposed slavery was that it was an economic threat to the economy of the North.

on this day in 1833, president andrew jackson announces that the government will no longer use the second bank of the united states, the country's national bank. a national bank had first been created by george washington and alexander hamilton in 1791 to serve as a central repository for federal fund