Praxis Earth and Space Sciences: Content Knowledge (5571 / 5572) Practice Test

The main idea being tested is how the origin of an air mass determines its temperature and moisture content. A continental polar air mass forms over cold, land-based regions, so it inherits very cold temperatures from the polar areas and has little moisture because it develops over dry land. That combination makes it describe cold and dry. When you think of other options, a warm and dry air mass would come from a hot, dry land source; warm and moist would come from a warm, water-rich source like oceans; and cold and moist would come from a cold oceanic source. So the cold, dry description best fits a continental polar air mass.