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The Cahokian civilization of Native Americans lived near St. Louis on the Mississippi River. According to items found in their cities, they were widespread traders. Archaeologists have found arrowheads from Oklahoma, shells from the Gulf of Mexico, stone objects from Wyoming, and salt from Illinois among many other things.
This paragraph tells mainly
a) where the Cahokians got salt
b) how widely the Cahokians traded
c) what the Cahokians used shells for
b) how widely the Cahokians traded