Answer:
USSR( United States of Soviet Socialist Republics )
Step-by-step explanation:
The collapse of USSR ended the cold war. The main reason for its collapse were the economic crisis that led to shortages and the policies of perestroika and Glasnost by Mikhail Gorbachev. Both these policies led to revolutions and demonstrations in the eastern bloc and the union collapsed on December 25, 1991 when the Mikhail Gorbachev resigned as the Soviet president. The events occurred during the presidency of George H. Bush and was the most important events .
Glasnost meant the policy of openness and press freedom, it shone light on the negative aspect of USSR. While perestroika meant economic and political restructuring of the society. These two reforms were not the sole causes of the disintegration of USSR but the forces they released destabilised already weak soviet union.