How did the mexican-american war ignite a conflict over slavery between the north and the south?

driven by economic ambitions and a sense that the United States was “destined” to span the entire continent, the war also raised the issue of how acquisition of such a large territory would affect the balance between slave and free states.

i don't get what you mean

explanation:

while it was true that the cotton gin reduced the labor of removing seeds, it did not reduce the need for slaves to grow and pick the cotton.

explanation:

before eli whitney's invention of the cotton gin, picking and cleaning cotton was a slow, labor-intensive job. workers, usually slaves, had to pick the seeds from the cotton fibers by hand. this invention made it possible to grow large amounts of cotton on big farms and make money.