Simplify the following text for a Grade 8 native English-speaking person.
Original: The term tundra comes through Russian Ñ Ñ Ð 1\/2 Ð Ñ Ð from the Kildin Sami word tÅ `` ndÃ cents r `` uplands , '' `` treeless mountain tract . ''
Simplified: The term `` tundra '' comes from tÅ `` ndÃ cents r which means ` uplands , tundra , treeless mountain tract ' .