Respuesta :

Levees held back the annual floods of the Tigris and Euphrates Rivers. and Surplus barley and wheat could be traded for other things.

Answer:

Levees held back the annual floods of the Tigris and Euphrates Rivers.

Explanation:

This method was also used in Egypt Empire. When floods seasons was comming, they built levees to prevent a disaster, but their crops were full of water, so during this period, The Pharaoh made them work in construction of the big buildings as other workers.