Final answer:
In the past, bartering was a common method of trade, which involved certain disadvantages. Money, first appearing as gold coins, simplified trade, and modern money today is mainly made of paper or ordinary metals.
Step-by-step explanation:
In ancient times, bartering was the method by which people exchanged goods, where they traded what they had in surplus for what they needed. This form of trade could be cumbersome due to the physical limitations of transporting goods, their perishability, or difficulty in dividing them into smaller units, hence, it had its disadvantages. With the introduction of money, particularly in the form of gold coins around 2,500 years ago, trade became more convenient and efficient. Modern money, unlike the gold used in earlier times, is predominantly made of paper or ordinary metals, simplifying exchanges even further.