Answer:
1) The expensive arms race in the USSR became an enormous burden on the struggling economy/Mass demonstrations for democracy put pressure on communist government.
2) Independent republics established democratic reforms and free market economy/The Cold War ended, leaving the United States as the world' sole superpower.
Explanation:
1) The decline of Soviet economy, the technological stagnation and the popular pressure for a more democratic regime due to the deterioration of their life standards, as well as the difficulties of keeping arms race due to low oil prices, led the Soviet Union on the verge of collapse.
2) The independent republics began relations with the United States and other Western countries and introduced Western-like reforms. The dissapearing of the USSR led to the finish of the Cold War, since there was no other superpower capable to deal with the United States in terms of army size, technology and ressources.
