Answer: Exchanging goods or services of equal value
Step-by-step explanation:
In society there is something called market. The market is a space, not always a physical one, where transactions of goods and services are made between an offering party and a demanding party. These parties can be actual persons or they can be companies.
Markets exist because ever since humans started living in society, there was always someone who needed something that another person had. That is, the market exists because there are needs that must be handled and someone has enough resources to cover them.