Ice wedging is when ice causes rocks to crack by expanding in openings, and ice wedging is the most important form of mechanical weathering. Given these facts, what is the most important part of mechanical weathering among the following options:
- roots and shoots
 - when they liquify
 - roots to grow
 - when it melds into soil
 - volcanic rock cracking
 - a tree falling
 - the looseness of soil
 - ice causes rocks to crack


 

        ice causes rocks to crack 