Eridu, Uruk, and Ur would be the answer.
One way that differed was that Africans were often sold by other Africans.
I hope this helps
The working conditions of the growing Russian industrial class in St. Petersburg and Moscow "<span>c. Were terrible and left the workers receptive to revolutionary propaganda," since there were no laws that protected workers' rights or safety at this time. </span>
Answer:
They had no goods to trade
