Neither. Russia is the most Eastern European country.
The nation that is furthest west on the continent of Europe is Portugal. However, Iceland is further west but is an island. It has been traditionally part of Europe.
Britain is part of the United Kingdom. The United Kingdom is a member of the EU, so Britain is therefore part of it.
You can drive in Great Britain on a full, valid driving licence from another EU country until you're 70, or for 3 years after becoming resident in Great Britain, whichever is longer.
If by "left-most" you mean looking down at a map, the farthest WEST is Iceland by technicality, although it is not a member of the EU, it is on the European continental shelf, the farthest West in countries which touch is Portugal, and the farthest West in the generally accepted European cluster is Ireland.
Britain is just one of 28 members. It is an important country in Europe, but the EU can function without it. What was then the EEC was formed in 1957 by six countries. Britain did not join until 1973. So it was 16 years without Britain being involved. The EEC evolved and more countries joined and it is now called the EU. The EU may need to reform as a result of the decision of Britain to leave, to change some of the reasons why Britain felt it should leave. It will take time for Britain to leave and there is even the possibility that they will decide not to.
If you are EU citizen from one country to another EU country, you pay tax, which vary from one EU country to another.
Great Britain is composed of England, Wales and Scotland. The UK is Britain + Northern Ireland. To join the EU as Great Britain would be to exclude Northern Ireland from the EU.
Yes, because both Sweden and Britain are in the EU. As a British passport holder you are also an EU citizen, which gives you the legal right to live and work in any other EU country.
No. free movement of labour across EU borders is a fundamental right in the EU.
Because we would have to stay in the EU if we didnt!!
No, because Andorra is not in the EU. The smallest country in the EU is Malta.