Why have many countries replaced their national currencies with the euro?i’m super

Originally, the euro was an overarching currency used for exchange between countries within the union while people within the countries continued to use their own currencies. 

Aregion is an area of land that has common features. these features can be natural, such as climate or landscape. they can also be artificial, such as language or religion. the xinjiang uyghur autonomous region, above, is an area of china inhabited by uyghurs, a muslim group with ethnic ties to turkish people.