During Hoover's administration, the stock market collapsed. This was such a huge deal because people were borrowing money from the banks and putting in stock market. When the collapse occurred people were unable to repay the banks the money they took out, the banks failed.
"They developed an extensive system of paved stone roads" is the one factor among the following choices given in the question that a<span>llowed the Incas to use their military efficiently. The correct option among all the options that are given in the question is the first option. I hope the answer helped you.</span>
Assuming that the time period is the mid-17th century, this is essentially the Slave Trade, where many Africans were brought into America to work on Plantations