Ans. While the US Dollar is the official currency of the United States of America, it also acts as legal tender in the territories acquired by the USA and even some sovereign nations around the world. Ecuador, Republic of Zimbabwe, Commonwealth of Puerto Rico, Virgin Islands, Marshall Islands, Guam are few of the names where USD can be used to transact. The U.S. dollar is also widely used throughout the world as a quasi-currency of exchange. Canada and Mexico are the vibrant examples where you can use USD as a quasi-currency for trade-related purposes.