Which of the following systems of trade was most widely used in both ancient river civilizations and ancint native american civilizations.

A:Bartering

B: the exchange of coined money

C: free exchange

D: international trade

Bartering

Explanation:

The ancient civilizations started bartering at the dawn of civilization. it is interesting that similar things can be found on the soil of American continent.

When they were in need of some certain product they didn't have, they would enter the bartering by offering some other products they had in exchange.