Fact 1: Erosion can cause a landslide.

Fact 2: Landslides indicate unstable terrain.

Given the two facts above, answer the question "what can erosion cause?" with the following options: 
- hurricanes
 - h2o
 - Pollution
 - slow and inefficient
 - unstable terrain
 - Physical weathering
 - flooding
 - hydrogen


 

     unstable terrain    