ANSWER:
The mountain range which separates the "Northern European" and "West Siberian plains" is the Urals or Ural Mountains.
EXPLANATION:
- They divide Russia into 2 parts, i.e., Europe and Asia and acts as a natural barrier to it.
- They are the oldest mountains having a span of about 300 million years ago.
- Mount Narodnaya is the highest peak of Ural Mountains and it runs from north to Ural river in south and finally the river flows in Caspian Sea.
