C. Geology
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Instead of the troika coming, there was a power struggle and Stalin took control of the country. He managed to remove all his political opponents and collectivize the properties which led to a rapid industrialization. There was no troika because Stalin ruled himself with an iron fist. He stayed in that position until he died in 1953.
D. <span>There was a power struggle between Stalin and Trotsky, and Stalin won.</span>
Nutrient - a nutrient is a substance used by an organism to survive, grow, and reproduce.