What do Russia, the Caucasus, and Central Asia have in common?

(1 point)
Responses

They all live in mountain areas.
They all live in mountain areas.

Many different ethnic groups live in each area.
Many different ethnic groups live in each area.

All people in all areas only practice Islam.
All people in all areas only practice Islam.

Russian is the most common language.

Russian is one of the most commonly spoken languages in these areas.