Final answer:
Lake Onega is the lake east of Lake Ladoga, connected by the Svir River. It is Europe's 2nd largest lake and part of the network of waterways involving the Volga River.
Step-by-step explanation:
The lake that is east of Lake Ladoga, is the 2nd largest in Europe, and is connected to it by the Svir River, is known as Lake Onega. Lake Onega is indeed a significant lake in Europe and plays a critical role in the region's ecosystem and economy. Like Lake Ladoga, it is part of the extensive network of waterways that includes the Volga River, which is vital for transportation, fresh water, and fishing in Russia. The Volga River, being the longest river in Europe, flows through Russia's core region and connects major industrial centers, linking Moscow to the Caspian Sea, as well as connecting the Caspian Sea to the Black Sea through a canal system.