You are presented with the question "What is a form of mechanical weathering?" and the following answer choices: 
- microbes breaking down rock
 - By coral exoskeletons
 - wind and erosion
 - oxygen breaking down rock
 - ice expanding in rock openings
 - removal of rock by acid rain
 - remains of prehistoric life
 - fissures of hot, acidic water

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.


 

     ice expanding in rock openings    