Final answer:
Under Catherine the Great, Odessa and Petropavlovsk were added to Russia's territory through her territorial expansion and modernization efforts.
Step-by-step explanation:
Under the ruler Catherine the Great, the territory of Russia was expanded to include Odessa and Petropavlovsk. Catherine the Great ruled from 1762 to 1796 and was known for her territorial expansion and modernization of Russia. She annexed Crimea, parts of Poland, and expanded into the territories that included Odessa and Petropavlovsk.
Catherine the Great was the ruler under whom Odessa and Petropavlovsk were added to Russia's territory, reflecting her expansionist policies aimed at modernizing Russia.
Odessa and Petropavlovsk were added to Russia's territory under the ruler known as Catherine the Great. This development occurred during her reign in the 18th century, where she sought to expand the Russian Empire. Notably, Catherine the Great was an 'enlightened despot' and her rule, although authoritarian, aimed at modernizing and westernizing Russia in order to secure and expand its borders.