What do Russia, the Caucasus, and Central Asia have in common?%
people in all areas only practice Islam.
people in all areas only practice Islam.%0D%0A%0D%0ARussian is the most common language. %0D%0ARussian is the most common language. %0D%0A%0D%0AMany different ethnic groups live in each area.%0D%0AMany different ethnic groups live in each area.%0D%0A%0D%0AThey all live in mountain areas.