Answer :
When ice freezes it expands. And when roots grow, they also expand. So when water pools in a crack and freezes, it forces that rock apart just a little bit. And over the course of decades, the process can repeat so many times that it splits the rock in two. The same goes for roots. They fit in a little space at one point but expand continuously and can eventually split the rock.
Ice wedging and plant root growth are similar, since, basically, both occur when mechanical weathering occurs. Mechanical (or actually, in this case, you can say biological weathering) means when either forces of nature, or extreme force act upon something, (in this case, a rock), to divide it into two parts. So, ice wedging is when--- water seeps into a crack of a rock, and when freezes, expands, so the crack widens. Water is a force of nature, so we can conclude that it will occur due to mechanical, or biological weathering. (you will get credit, most likely, for both). Plant growth in a rock is also considered biological weathering, as well as mechanical, because-- Well, obviously, :) plants are a force of nature as well. I really hope this helps! Please rate as brainliest if possible! Thank you!