✔ 最佳答案
Some brief points which you can build on:
1. bigger flow of currency as more nations' economies function in one single currency --> greater supply of and demand for such currency (as a good) --> greater dominance and influence on the world's economy.--> avoid major, fierce competition with other outside-EU economies.
2. the Euro zone -- countries of the EU have stabler prices of exports and imports when trading within the EU --> avoid extra costs such as commission on foreign currency exchange, and taxes --> also demand for exports from other EU countries is increased as costs are lower.
3. Small and weaker economies e.g. Romania gain higher access to trades outside the EU e.g. the USA, as a whole alongside with other powerful economies e.g. Germany than on their own.
4. Small and weak economies may not be able to survive without the enforcement of economic policies from the EU due to various factors e.g. weak government and lack of resources. The EU decides on which policies the union will take to increase their competitiveness which are beneficial (although vastly to the more powerful economies) and so in theory these small economies will not be suffering from downturn of economy (or at least one expects).
And so on.
I think it will be worthwhile of you to go on the EU website and find out what this currency is all about. You may come up with some ideas of your own afterwards.
And the last piece of advice from me: since this question sounds quite a long and analytical one to me, you may want to give both points of view to attain higher grades e.g. why has the UK decided not to join the currency.
hope it helps.
2011-10-21 11:08:51 補充:
One thing to be added, you want give an example of 'greater dominance and influence on the world's economy', that is bigger purchasing power.