Why did communism in the soviet union collapse in the late 1980s?

consider:

political factors: what did leaders in the soviet union, the united states, and europe do to further the fall of communism?
military factors: what effect did military policies and actions in the united states and in the soviet union have?
economic factors: what effect did the economic situation in the soviet union have?
social/cultural factors: what was the attitude of the people of the soviet bloc countries? what impact did glasnost have? what was the impact of dissidents?

the Soviet Union fell due to World War 2, when the Allied Nations defeated the Natzies.

Gorbachev's decision to allow elections with a multi-party system and create a presidency for the Soviet Union began a slow process of democratization that eventually destabilized Communist control and contributed to the collapse of the Soviet Union.

part a. there were 250 teenagers surveyed (100% of tenagers = 250)therefore 1 % = 250/100 = 2.5 76% = 1% x 76 = 2.5 x 76 = 190 teenagers of the 250 surveyed liked burgerspart b: jane surveyed 25% (which is equal to 50 teenagers, i.e. a quarter of the teenagers surveyed is 50) to get 100% we simply get 4 quarters, i.e. multiply 50 by 4 = 200 teenagers were surveyed by jane. part c: it is impossible to give an example where a percentage is greater than 100%, since, by definition , percentage means "per 100".

basic principles: federalism, separation of powers, checks and balances, judicial review, representative democracy, limited government, rule of law, individual rights and responsibilities, consent of the governed, majority rule, popular sovereignty, equal protection.