What are the major elements of great Britain?

Great Britain does not have any "major elements". The term "Great Britain" refers to the island that comprises England, Scotland, and Wales. As a political entity, "Great Britain" existed from 1707 to 1801. In 1801, Ireland was added to create the United Kingdom of Great Britain and Ireland (colloquially known as the United Kingdom or UK). After Irish independence in 1922, only Northern Ireland remained a part of the UK. Therefore, in the present geographical, historical, and geopolitical contexts, the main or major political elements of Great Britain refer to its constituent countries England, Scotland, and Wales (with Northern Ireland sometimes included as the fourth constituent country when referring to the wider context of the UK).