Which factor is unique to the city-states of Mesopotamian civilizations? A. location along the Tigris and Euphrates rivers
B. dry, arid weather
C. evidence of monumental architecture
D. remains of a settlement

It is A. (Location along the Tigris and Euphrates rivers )

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.

he risk-return relationship. generally, the higher the potential return of an investment, the higher the risk. there is no guarantee that you will actually get a higher return by accepting more risk. diversification enables you to reduce the risk of your portfolio without sacrificing potential returns.

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