Interchangeable parts were first used by Eli Whitney in the cotton gin in 1798
In the 19th century, Americans began to move west, causing the displacement of many native Americans.
Answer : A, once policies are written into state constitutions they become harder to change, requiring a new constitutional amendment.
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After the war, the land had been changed with territory expansion otherwise.
farmland became extremely expensive and the remaining small farms could not compete with the larger newer farms that excelled out of the war.
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