Answer:
Imperial Russia was the largest, but in the same time one of the most undeveloped countries in Europe. Losses in the war led to further complication of social relations between the members of the society. Large gap between rich and poor, hunger and riots were leading towards the decline of previous regime. People started asking for war to end, wealth (land) to be redistributed and hunger to be eradicated. Finally, revolution totally overthrew the old regime and socialism was established in the country.
Step-by-step explanation:
Russian involvement in WW1 was a complete fiasco. They were losing the war, but situation in the country was also awful. People started rebelling and riots were quiet often. That led to February, and after that October Revolution. Socialism started spreading not only in Russia, but even outside of this country.