Which empire did not have a written system for communication? a. incas c. olmecs b. mayan d. aztecs

The answer should be A, the Inca used fast roadrunners to relay messages. It was a specialized and honorable profession that required studies. Since the Inca had no writing system the runner had to remember the message, and relay it to the next person. 

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Herbert Hoover earn the nickname “The Great Humanitarian?” because he sent massive amounts of food relief aid to Europe, mostly to the Belgians and the French, who had suffered under years of German occupation.