one important effect of the invention of the cotton gin in 1793 was it dramatically reduced the amount of time it took to separate cotton seeds from cotton<span> fiber.</span>
C because the key word effect so answer c say's some thingthing about it "establish" meaning later on, also stock exchange would be something major because it allowed them to have new things they could never get in there own country.
I think that the answer is A
The civil war improved the economy of the north, but harmed the economy of the south. The south relied heavily on agriculture/ producing cotton on slave worked plantations. The civil war led the slaves to finally be freed thus sending many southern farmers into poverty.
