Final answer:
The Soviet Union no longer exists due to internal political struggles, economic issues, and independence movements within its republics, culminating in its dissolution in December 1991. Russia still exists as it was the largest republic and successor state of the Soviet Union, maintaining its international presence post-dissolution. The collapse of the Soviet Union led to the independence and democratization of its former republics and Eastern European states.
Step-by-step explanation:
The Soviet Union no longer exists because of a series of events in the late 1980s and early 1990s, including economic struggles, political reforms, and movements for independence within its constituent republics. The implementation of policies such as perestroika and glasnost under Mikhail Gorbachev aimed to revitalize the Union, but instead, they gave rise to liberation movements and weakened the Soviet government's grip. The culmination of these events was the attempted coup against Gorbachev in August 1991, Boris Yeltsin's rise to prominence, and the subsequent agreement between the presidents of Russia, Belarus, and Ukraine to dissolve the Soviet Union in December 1991.
Russia still exists because it was the largest republic within the Soviet Union and effectively became its successor state after the dissolution. Under the leadership of President Boris Yeltsin and later Vladimir Putin, Russia reestablished itself as an independent country separate from the Soviet political system. Despite the end of the Soviet Union, Russia retained much of its international presence and significance, particularly due to its status as a major nuclear power.
The aftermath of the Soviet Union's dissolution saw other former Soviet republics and Eastern European states asserting their independence and transitioning towards democracy and free-market economies. These states sought integration with the European community and some became members of international organizations such as the EU and NATO. The transition, however, has been marked by conflict and geopolitical struggles, particularly with Russia's attempts to reassert its influence in the region.