C. Using a specific model to prove the earth moving around the Sun.
I assume you mean what challenges after they gained independence. They had many internal conflicts. This included fighting about religion. There were also natural disasters. There was the problem of transitioning directly from a dictatorship to a democracy.
In Russia, World War I became the catalyst for the ovethrow of Czar Nicholas II and the rise of the Communist Party (Bolshevik Revolution) led by Vladmir Lenin. Russia became the first Communist country. Communism eventually spread to small countries near Russia and eventually spread to Cuba, China and Vietnam.
Watson and Crick is the answer
