Answer:
1. Oleg, a Varangian, unites several cities into Kievan Rus.
2. Batu Khan and his skilled Asian horsemen make Russia part of the Mongol Empire.
3. Peter the Great modernizes Russia and founds Saint Petersburg.
4. The October Revolution brings Marxist Vladimir Lenin to power.
5. Mikhail Gorbachev introduces perestroika reforms to overhaul the Soviet Union.
Explanation:
