Complex sentence: Cross-country skiing (or XC skiing) is a form of ski touring in which participants propel themselves across snow-covered terrain using skis and poles which is popular in many places with large snowfields, primarily Northern Europe, Canada, and Alaska.
Split into simpler sentences: Cross-country skiing (or XC skiing) is a form of ski touring in which participants propel themselves across snow-covered terrain using skis and poles. The activity is popular in many places with large snowfields, primarily Northern Europe, Canada, and Alaska.