11. the sumerians first used for trade, but later switched to because .

the most famous of all the units fighting in cuba, the "rough riders" was the name given to the first u.s. volunteer cavalry under the leadership of theodore roosevelt. roosevelt resigned his position as assistant secretary of the navy in may 1898 to join the volunteer cavalry. the original plan for this unit called for filling it with men from the indian territory, new mexico, arizona, and oklahoma. however, once roosevelt joined the group, it quickly became the place for a mix of troops ranging from ivy league athletes to glee-club singers to texas rangers and indians.

a causal relation between two events exists if the occurrence of the first causes the other. the first event is called the cause and the second event is called the effect. a correlation between two variables does not imply causation.

explanation:

) the chinese armed forces had been removed from the city