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.
Economic causes of wars were most important. Divisions over religious principles and authority underlay most wars, hope this helped <3
Answer:
Running water and internal drainage systems were used to make them more safe and more sanitary to live in. The workers wages were also increased and workers could find jobs in the city.