Why did france britain and italy agree to give the sudeten territory to germany?

That's because they wanted peace. It was the policy of appeasement. If they gave him what he wanted, that would solve his problems and keep the peace in Europe intact. They were however as it was only a matter of time before the war began, and it did with the invasion of Poland.

It is the doctrine that the us had the right and duty to expand throughout north america. it just means they believed they had the right to expand westward and they did! they stated with the 13 colonies and then they kept moving gaining different territories throughout the years

Are there any words that will you