Catherine the Great significantly changed Russia through several key initiatives. The correct answers in the context of how she influenced the country would be:
A) She modernized and Westernized it - Catherine promoted Western European culture, ideas, and practices in various aspects of Russian society, including art, education, and government.
B) She reformed Russia's economy - She implemented economic reforms that encouraged trade and agriculture, improving the overall economic structure of the country.
D) She expanded Russia's territory - Catherine led military campaigns that significantly expanded Russian territory, including conquests in the Black Sea region and parts of Poland.
C) She founded the Kievan Rus is not correct in this context, as the Kievan Rus was established centuries earlier, in the 9th century, long before Catherine's reign in the 18th century.
In summary, the correct answers regarding Catherine the Great's changes to Russia are A, B, and D.