Which word refers to any system that uses an exchange medium-whether its a precious metal or government-printed paper-that can be traded for other goods

Any system that uses a medium for the exchange for other goods, uses money. Money is an exchange medium that can be in the form of coins, banknotes or some other precious metal. It has its value, which is determined on the basis of many economic parameters, and this value depends on the economic stability of the state. Each country has its own currency as a medium of exchange in transactions, in sense that everyone in the economic transactions agrees to accepts that money.

"choosing is refusing" means individuals face an opportunity cost with each decision they make. economists state that every decision involves trade-offs. opportunity cost is the least desirable alternative given up as a result of a decision.