Juan manuel de rosas mainly kept law and order in argentina by using terror and tyranny. earning respect and cooperation. imposing harsh fines. enlisting aid from abroad.

option a

explanation:

to cleberate the end of their war

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.