What are the factors that led to the fall of the soviet union?

Which of the following statements best describes the spread of communism in the years immediately following world war ii? a. the number of communist countries increased during these years. b. the number of communist countries decreased during these years. c. the number of communist countries stayed the same during these years. d. the number of communist countries increased in asia but decreased in europe. ( answer in the format above for me to understand)

How did the technology of the late 1800s affect the growth of cities? select one: a. cities were able to expand outward because of additions to railroads. b. electric streetcars enabled the wealthy city dwellers to move to the first suburbs. c. advances in steel and metal technology allowed for the development of the skyscraper, which allowed cities to grow upwards. d. all of these are correct.

The quote below is an excerpt from the charter of the united nations: "the purposes of the united nations are: to maintain international peace and security, and to that end: to take effective collective measures for the prevention and removal of threats to the peace, and for the suppression of acts of aggression or other breaches of the peace, and to bring about by peaceful means, and in conformity with the principles of justice and international law, adjustment or settlement of international disputes or situations which might lead to a breach of the peace . " source:this section implies that the united nations is prepared to do what to keep world peace?