Why were African Americans particularly harmed when the stock market crashed?.

The stock market crash of 1929 was not the sole cause of the Great Depression, but it did act to accelerate the global economic collapse of which it was also a symptom. By 1933, nearly half of America's banks had failed, and unemployment was approaching 15 million people, or 30 percent of the workforce.

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).