Different monetary unit of all countries?

Each country has its own monetary unit, often referred to as its currency. For example, the United States uses the dollar (USD), the Eurozone countries use the euro (EUR), Japan uses the yen (JPY), and the United Kingdom uses the pound sterling (GBP). Some nations, like Ecuador and El Salvador, even adopt the currency of Another Country, such as the U.S. dollar, as their official currency. Currency values fluctuate based on economic conditions, making exchange rates crucial for international trade.