Final answer:
Barter is the practice of trading goods and services without using money, which was common before the development of money as a medium of exchange, simplifying trades and transactions.
Step-by-step explanation:
Barter is the practice of trading goods and services without the use of money. This system of exchange can be traced back to the very beginnings of human society and has evolved over time. In a barter system, a double coincidence of wants is required, meaning each trader needs to have something the other wants. For instance, an accountant seeking a pair of shoes needs to find someone who not only has the shoes but is also willing to trade them for accounting services. The development of money as a medium of exchange significantly changed the way goods and services are circulated within an economy, overcoming the inefficiencies inherent in the barter system. Money, taking many forms throughout history such as cowry shells or precious metals, is agreed upon as having value within a culture and is used for transactions, greatly simplifying trade and exchange.