The document defines several economic terms related to international trade, scarcity, and currency exchange. It explains that scarcity refers to wants exceeding supply, quotas limit imports into a country, and currency is money accepted as a medium of exchange, usually paper money. Trade barriers like tariffs, quotas, and embargoes can be used by governments to restrict trade between countries, with tariffs being fees charged on imported goods and embargoes blocking certain imports and exports through potential military force. Currency exchange rates refer to the price of one country's money relative to another's and can be fixed or flexible.