Answer:
After societies evolved from hunter-gathering, to pastoral, and then to agrarian, one activity emerged between them, especially as agrarian societies settled lands, instead of continuing being nomadic, this was: trade.
Trade, during those times, was not influenced by the desire for having more, or having power, or having money, because these societies were pretty small, and what they produced, at least at first, was barely enough to feed themselves. However, as technology grew, and new means of production arose, agricultural, or agrarian societies began to see surplusses of food and they soon found that these could be used to trade with other groups that had settled nearby. It was agriculture, and trade, which drove these societies to further develop, grow, specialize and settle the lands. From them, civilizations began to grow.
What is pictured in this cartoon, therefore, is the initiation of the discovery that goods, especially when there was a surplus of them, could be exchanged for the goods of other groups, and which the original producers could, or did not, have. Thus trade emerged. But this was a trade in which currency, and money, played no part; this trade was driven by the desire to obtain that which a farmer´s land could not provide, or was provided in very small amounts.