Who was the leader of the nazi party and the head of the totalitarian regime in germany

Adolf Hitler. He led Germany under a dictatorship/authoritarian/autocracy/fascist rule.

a case involving the laws of a single state.

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.