If moist, cold climates cause rocks to crack by ice expanding in openings, then what causes rocks to crack from ice expanding into openings?

Answer choices:
- evaporation
 - In the winter
 - tropical climates
 - heat energy
 - hot, dry climates
 - moist, cold climates
 - colder weather
 - Inches or fractions of inches.

 

      moist, cold climates    