In a federal system a discrit court has the power to

The United States district courts are the general trial courts of the United States federal court system. Both civil and criminal cases are filed in the district court, which is a court of law, equity, and admiralty.

Explanation:

c]extended voting rights to african americans

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).