A reason why the Civil War lasted four years is that the Union had to fully conquer the South.
The earliest Chinese people did not have to worry about invasions from foreign countries because of their strong army and geography. The Chinese army present in ancient times were very strong and able to defend their lands. Chinese also build china wall in order to protect their lands from the invasion of other people. The geography of china also made difficult for the invaders to capture china.
The answer is B. Three days
The Cold War Containment policy was a complete bust because we pour money into failing countries so they there economy was strong enough to where they wouldn't have radical thoughts of communism this was referred to as the Truman doctrine and then the Eisenhower doctrine that funded the middle east. Then we went into the police action "war" in Korea so that the domino effect wouldn't allow other nations to fall to communism