Money has evolved over time from barter systems to various forms of commodity and metallic money to modern paper and bank money. Early civilizations relied on self-sufficiency, but agriculture led to specialization, trade, and the need for a trading mechanism, resulting in barter systems. However, barter presented difficulties like the double coincidence of wants and lack of a common measure of value. This led to the use of commodity money like shells, tea, and cattle. Metallic coins using gold, silver, and other metals further developed as money. Paper money originated from receipts issued by goldsmiths for safekeeping of valuables, which became banknotes. Today, most money takes the form of bank deposits that can be