Fact 1: Ice wedging is when ice causes rocks to crack by expanding in openings.

Fact 2: An ordinary ice road is therefore severely damaged by cracks induced by the traffic.

Given the two facts above, answer the question "Ice wedging causes what to be severely damaged?" with the following options: 
- an object
 - ice roads
 - lights
 - fields
 - trees
 - vehicles
 - arteries
 - coastlines


 

  ice roads       