What was the cause of the Bolshevik establishment of the Union of Soviet Socialist Republics?
A. After victory in the Russo-Japanese war, Russia had gained a significant amount of new territory.
B. Revolutionary leader Vladimir Lenin promised to solve Russia’s economic problems through communism.
C. The Red Army had sided with revolutionaries, and a new military and political system had to be established.
D. White Army leader Alexander Kerensky signed a peace treaty with the Allied powers.

Primary causes of the Russian Revolution included widespread corruption and inefficiency within the czarist imperial government, growing dissatisfaction among peasants, workers, and soldiers, the monarchy's level of control over the Russian Orthodox Church, and the disintegration of the Imperial Russian Army.

How did the Bolsheviks create the Soviet Union?

After forming their own party in 1912, the Bolsheviks took power during the October Revolution in the Russian Republic in November 1917, overthrowing the Provisional Government of Alexander Kerensky, and becoming the only ruling party in subsequent Soviet Russia and later the Soviet Union.

Learn more about the Bolshevik revolution here https://brainly.com/question/15319376

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