Examine the dual role of structures as barriers to, and facilitators of, global flows. are subtler structural barriers more effective than material barriers?

To solve their problems, mesopotamians used irrigation, a way of supplying water to an area of land. to irrigate their land, they dug out large storafe basins to hold water supplies these ditches brought water to the feilds. to protect their feilds from flooding, farmers built up the banks of the tigris and euphrates.hope ths !

The correct answer is "  it was believed that the dispute emerged in 632 just after the death of the prophet muhammad."