Why did great Britain go to war against Germany?
so that Germany wouldn't take over the entire continent.
Great Britain is the name of an island not a country. Do you mean the UK? The name of the country is 'The United Kingdom of Great Britain and Northern Ireland', often abbreviated to 'The UK', 'Britain' or 'Great Britain'. During the Great War Britain was allied with France and Russia against Germany and the Austro-Hungarian Empire.
Great Britain Became involved in World War II because one of its allies, Poland was attacked by Germany. When Germany refused to withdraw Britain declared war on Germany. A year later, France and Western Europe were occupied by Germany and Britain was the last bulwark against Nazi domination. As had happened in World War I, the US entered the war belatedly (in late 1941) and allowed Britain and the Allies to persevere in their efforts…