B the right to public trials.
The people were to give/reserve their lives to propitating the gods to prevent terrible events from happening to the community. The political structure of Sumer was independent city-states. The map shows the important communities. Note that in Sumerian times the Persian Gulf extended to the area of the city-states.
The triangular trading system was not only used to sell/buy slaves, many countries benefitted from other resources that were scarce in their lands. The thirteen colonies would trade fish, whale oil, lumber, tobacco, rum, iron products, flour and meat products and England and Europe would trade teas, spices, furniture, cloth, tools, iron products, etc. New England specifically would trade with the Caribbean for sugar (or molasses) and New England would distill it into rum. The profits from the sale of the sugar would be shipped to West Africa where the majority of slaves came from, and the slaves were sent to the Caribbean to work on sugar plantations.
