Americans pushed native americans out of their territory. This was a selfish act from the U.S. and shows how much they wanted for themselves, and didn't care about others. New agricultural machinery allowed farmers to increase crop yields with less labor, but falling prices and rising expenses left them in debt.
Answer: The yellow river is located at (LETTER B) The structure built to keep out the northern barbarians was called the (Great Wall) and is located at (LETTER C) The Silk Road is located at (LETTER A)
