The correct answer to this open question is the following.
Although there are no options attached, we can say the following.
Stalin failed to act quickly on promises to help the U.S., according to the agreements reached during the Yalta Conference and later in the Potsdam Conference. However, the United States also failed to do things agreed upon during the conferences. Of course, both nations have their own sides of the story. The real thing was that these series of disagreements contributed to mistrust between the nations.
During the so-called Cold War years, the Soviet Union remained in control of Czechoslovakia, East Germany, Romania, Bulgaria, Poland, and Hungary. Stalin considered these countries as a buffer in case the western allies tried to invade the Soviet Union.
The Cold War years was a time in which the United States and teh Soviet Union competed in the arms race, the space race, and in spreading/contain Communism in the world. These generated so many conflicts and wars around the world.
ANSWER:it is cause for twenty-five percent of the national budget
Invasions by Barbarian tribes. ...
Economic troubles and overreliance on slave labor. ...
The rise of the Eastern Empire. ...
The most important reason for the collapse of Rome was the failure to actually integrate what they conquered. When Roman soldiers conquered new lands, it was rare that they ever attempted to force their culture, ideals, or laws upon the natives and barbarians. Thus, when the Empire began suffering internal struggles, the natives they had conquered decided to take action, which lead to the swift collapse by barbarian invasion from all sides. It's hard to pick a LEAST important reason, seeing that there were many of them, but I suppose a contender would most likely be the common refusal of the Empire to even acknowledge that barbarians were rising. On the outer edges of their territory, in places like Gaul and Morocco, the Roman government was reluctant to even recognize the threat of the barbarians, thinking that even accepting that these barbarians were causing trouble would weaken their prestige in the public eye.