Obsidian is natural glass from volcanic activity: how sharp can a flake edge of this material be? What about the edge of a flake of chert or flint?

i would say your answer is a)

sorry if im wrong

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.

a.impressment of us soldiers