Buying on margin was a method of buying stocks

  Buying on margin was a method of buying stocks with mostly borrowed money. The stock market crash caused the Great Depression. One cause of the Great Depression was that, in response to workers' demands, wages rose faster than corporate earnings, causing factories to go bankrupt.

zheng he was a chinese explorer who lead seven great voyages on behalf of the chinese emperor. his seven total voyages were diplomatic, military, and trading ventures, and lasted from 1405 – 1433. however, most historians agree their main purpose was to promote the glory of ming dynasty china.

explanation:

d: their own individual powers within the new goverment