Деревяный брусок обьёмом 300 км3 имеет массу 120 г. Найдите плотность дерева.
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Britain which is formally known as the United Kingdom of Great Britain and Northern Ireland is the political unity of England, Scotland, Wales and Northern Ireland. 
It is located on the British Isles
Its total area is about 244 thousand square kilometres. 
The coasts of the UK are washed by seas of 2 oceans:  the Arctic and the Atlantic.
The scenery is the coastline is rather picturesque.
The capital of the UK is London.
The official language is English.
The national symbols of the UK are the Red rose and the Lion, the flag 'Union Jack', and the anthem 'God Save the Queen'.
Its form of government is a constitutional monarchy.
Officially the supreme legislative authority is the Queen in Parliament
and the two Houses of Parliament .and the elected House of Commons. 
But The Queen officially opens each Parliamentary session.
The  three major parties are the conservative party, the new labour party, and the democratic liberal party.
The largest cities are Birmingham, Glasgow, Liverpool, Manchester, Edinburgh, Belfast and Cardiff.
The chief river is the Thames River 
Britain's major industries include  iron and steel engineering, shipbuilding, electronics.

My native city is Rostov-on-Don. It is the capital of the Don area. It was founded in 1749. It is situated on the right bank of the river Don.

In the past Rostov was a small town with small population. But now the territory of Rostov-on-Don is 380 square kilometres and the population is more than one million people.

Our city is a big industrial, scientific and cultural centre in the South of Russia. The plant “Rostselmash” is known not only in our country but abroad as well.

The largest scientific and educational establishment is the Rostov State University, which was founded in 1915 and now has more then ten faculties.

In Rostov there are four theatres: Gorky Drama Theatre, Musical Comedy, Puppet Show, Theatre of Young Spectators. The Gorky Theatre is surrounded by a large park named after the October Revolution. It is one of many parks and gardens which make Rostov a green town and where Rostovites like to walk on a nice sunny day.

During the Second World War Rostov-on-Don was occupied twice (1941 and 1942). The war cost Rostovites huge losses in life. That is why in the city there are a lot of monuments devoted to the war years and people who gave their lives for our peaceful life.

Rostov-on-Don is a large transport centre. It is not only a big knot of railways and airways but it is also the port of five seas (the Baltic, the White, the Caspian, the Black and the Sea of Asov).

Nowadays Rostov-on-Don as many other cities and villages in Russia is undergone the process of economical changes. But we hope that in some years people will be able to overpass all the difficulties and Rostov-on-Don will occupy its place of one of the biggest industrial cities of Russia.