Nations governed only by one central government are known as systems

in 1897, pershing became a tactical officer at west point, and that's where he was given the nickname "black jack." pershing's first name is "john," for which "jack" is a nickname, and he was a white man who commanded black troops. hence "black jack".

he armenian genocide, also known as the armenian holocaust, was the ottoman government's systematic extermination of 1.5 million armenians, mostly citizens within the ottoman empire.

explanation: