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Boreal forests prevail throughout the country , ice is prominent in northerly Arctic regions and through the Rocky Mountains , and the relatively flat Canadian Prairies in the southwest facilitate productive agriculture .
 Arctic, Rocky Mountains, Canadian Prairies
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Arctic, Rocky Mountains, Canadian Prairies