Europe and asia
Ural Mountains divide Russia into Europe and Asia. The Ural Mountains are famous for the fact that they serve as a natural divider between the two continents: Europe and Asia. The Ural Mountains begin where the East European Plain ends. Immediately east of the Urals begins Siberia.
The Alps does not separate any continents.
They form the main boundary between Europe and Asia.
The Ural Mountains is located in Russia. It's a natural border between the two continents, dividing Europe from Asia and the other way around. Asia occupies Siberia and the Russian Far East in North Asia (the large part of Russia east of the Ural Mountains).
The Ural Mountains are the only mountains that separate two continents.
The Ural Mountains and the Caucasus Mountains separate Asia and Europe.
The Ural Mountains were formed by the continents of Europe and Asia joining together.
Only two mountain ranges separate the continents: Ural & Caucus Mountains.
Europe and asia
The Ural Mountains. They run north to south through Russia for about 2500km from just south of the Kara sea to the Ural river. Only two mountain ranges separate the continents: The Ural Mountains and the Caucasus Mountains.
Ural Mountains divide Russia into Europe and Asia. The Ural Mountains are famous for the fact that they serve as a natural divider between the two continents: Europe and Asia. The Ural Mountains begin where the East European Plain ends. Immediately east of the Urals begins Siberia.
There is no hard and fast answer to this and many geographers do not consider Europe and Asia to be separate continents as there is no logical physical divide between them. However, the most likely answers would be 'Ural mountains', 'Caucasus mountains' and the 'Bosphorus strait'. As the question asks for 'one of the boundaries', any of these should suffice.
Europe and Asia
Europe and Asia
The Alps does not separate any continents.
The Ural Mountains and the Caucasus Mountains.