The United States assumed that since the USSR was attempting to spread communism into Asia, countries around the main target would fall as well - the Domino Effect.
The United States fought to prevent the spread of communism by interfering in countries such as Vietnam and Korea - however, both outcomes were unsuccessful or did little to nothing.
Yes, they were correct as once Vietnam fell to communism so did Cambodia and Laos.
Hope this helps!
<span>The correct answer for this question is B - The one important effect of the development of monotheism is that it now forms the basis for three major world religions. A more accurate answer however might reference four major world religions - namely Christianity, Islam, Judaism and Sikhism.</span>
The evacuation of Dunkirk