Short answers, pulled from the story.
Great Britain is an island in the North Atlantic Ocean off the north-west coast of continental Europe, made up of England, Scotland and Wales. It is the largest of the British Isles, the largest European island, and the ninth-largest island in the world.
Great Britain covers an area of 209,331 square kilometres. In 2011 it had a population of about 61 million, making it the world's third-most-populous island after Honshu in Japan and Java in Indonesia.
The name Britain descends from the Latin Britannia, the land of the Britons, which the Romans used from the 1st century BC. The word "great" came from Ptolemy, who in his Almagest around 147 to 148 AD called the larger island great Britain and Ireland little Britain.
The term Great Britain was first used officially in 1474, in the instrument proposing a marriage between Cecily, daughter of Edward IV of England, and James, son of James III of Scotland. That document described it as "this Nobill Isle, callit Gret Britanee".
No. Great Britain refers to England, Scotland and Wales together, while the United Kingdom also includes Northern Ireland. The two countries were joined into the Kingdom of Great Britain when the Acts of Union took effect on the 1st of May 1707.
Great Britain became an island when rising sea levels reflooded the land bridge known as Doggerland by around 6500 BC. During the earlier Devensian glaciation the sea level sat about 120 metres lower, leaving Britain joined to what are now Denmark and the Netherlands.
Great Britain has modest animal diversity, with 628 bird species recorded and rodents making up 40 percent of mammal species. Its flora comprises 3,354 vascular plant species, and it is home to the Fortingall Yew in Perthshire, the oldest tree in Europe.