Because most of these are Islands or surrounded mainly by sea.
Scandinavia.
Iceland is considered a part of Scandinavia, and Scandinavia is a group of nations in northern Europe. The name of the continent of which Iceland is a part of is therefore: Europe.
The United Kingdom of Great Britain & Northern Ireland, off the northwest coast of Europe.
Ireland is not physically located on Europe. It is an island nation that is politically a part of Europe. It is located in Western Europe, west of the United Kingdom and north of France and the Iberian Peninsula.
Denmark is a country that is part of Europe. The reason why Denmark is sometimes (incorrectly) considered part of North America is that the island of Greenland, which is part of the kingdom of Denmark, is actually geographically in North America.
Yes. Continental Europe does not include island such as Great Britain and Ireland, or Scandinavia (the countries to the north including Norway, Sweden and Finland).
London is in the United Kingdom, which comprises of Great Britain and Northern Ireland. Great Britain is an island just off the coast of mainland Europe, but in general it is considered to be in Europe.
Asia.
The Baltic Sea for Sweden and Finland. The North Sea for Norway.
In the United Kingdom of Great Britain and Norther Ireland.
Northwestern European countries include Iceland, Ireland, the United Kingdom, Norway, and Denmark.The countries in Northwestern Europe include Iceland, Ireland, the United Kingdom, Norway, and Denmark.
Great Britain, Ireland, Northern Ireland, France, Iceland, Sweden, Norway Finland, Belgium, Luxembourg, The Netherlands, Denmark, Germany, Italy, and Scandinavia.