1) The United Kingdom of Great Britain and Northern Ireland (UK) is the correct and offical name of the country.
2)Britain is not official name of country.
3)The main countries of UK are England (London), Wales(Cardiff),Northern Ireland(Belfast), Scotland(Edinburgh).
4) Each part of UK has the national emblem. The Wales emblem is red Welsh Dragon. Other national emblems of Wales include leek(daffodil) too.
English emblem is red rose.Other emblems are:oak tree;Three Lions; St George`s Cross (the English flag).
Scottish emblem is a thistle because people in Scotland say that it saved their land from foreign invaders many years ago. And the Irish emblem isanother wild plant - a shamrock..Other national signs: flag of Scotland, known as the Saltire or St. Andrew's Cross;wild plant-shamrock.
5) When King James VI of Scotland inherited the throne of England and was crowned James I of England in 1603, the crowns of the Kingdom of England (which since 1535 had included Wales) and the Kingdom of Scotland were united in a personal union through him. Despite this Union of the Crowns, each kingdom remained an independent state.In honour of that Union flag was called Union Jack.
6)Wales is not represented on the flag because Principality couldn`t be included on the Union Jack.
7)The Flag of Wales incorporates the red dragon (Y Ddraig Goch) of Prince Cadwalader along with the Tudor colours of green and white. It was used by Henry VII at the battle of Bosworth in 1485 after which it was carried in state to St. Paul's Cathedral. The red dragon was then included in the Tudor royal arms to signify their Welsh descent. It was officially recognised as the Welsh national flag in 1959. The British Union Flag incorporates the flags of Scotland, Ireland and England but does not have any Welsh representation. Technically, however, it is represented by the flag of England due to the Laws in Wales act of 1535 which annexed Wales following the 13th century conquest.