What is a tariff? What are arguments for tariffs? What are arguments against tariffs?

Explanation: *What is a tariff is*

a tax or duty to be paid on a particular class of imports or exports  

              (what are arguments for tariffs is )

Governments may opt to impose tariffs for a multitude of reasons, including the following goals: To protect nascent industries. To fortify national defense programs. To support domestic employment opportunities.  

                       (What are arguments against tariffs? is ...)

Tariffs hurt exporters by making their products more expensive. They could struggle to maintain their sales, which could cause profits to fall and, potentially, the country's economy to shrink. Alternatively, exporters could decide to cut their prices to maintain sales, but this too could shrink their profits

these civilizations were located around fertile rivers, where they could produce an abundance of crops