You are presented with the question "When ice causes rocks to crack by expanding in openings, what is this called?" and the following answer choices: 
- In the winter
 - smoking
 - icing
 - fissures of hot, acidic water
 - mechanical weathering
 - graptolites
 - Inches or fractions of inches.
 - rocking

Now knowing that ice wedging is when ice causes rocks to crack by expanding in openings and ice wedging is the most important form of mechanical weathering, choose the best answer.


 

     mechanical weathering    