The exchange of one good for another

Exchanging goods is known as barter.

Bartering. This was how things were primarily traded before money was invented or during times of economic crisis (such as Germany after WWI, when the Mark was almost worthless). 

Hope this helps! 
-Astro, Helper-In-Training 

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 !

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