The US introduced industrial power and new weapons. To protect their country from being taken over by the US or another foreign power, Japan decided to become a "western" power. The US opening Japan to trade exposed them to the methods of a modern country.
a smaller industrial base, fewer rail lines, and an agricultural economy based upon slave labor made mobilization of resources more difficult
The main reason why the twenties are sometimes called an "age of prosperity", especially in the United States, is that "<span>A.Incomes throughout the United States grew and the middle class held most of the wealth," due mostly to speculation in the stock market. </span>
<span>Based on what I know about the Cold War and the quote you gave above I would choose this option: It showed that democratic nations were facing a threat from Soviet expansionism.
Churchill had no plans to attack the Soviets or liberate these states. It was merely about pointing out the spreading of communism and that the western nations should join forces to contain it.</span>
