Fact 1: Sand dunes are formed by the wind transporting and depositing sand.

Fact 2: Dune grass is very important to the preservation of sand dunes.

Given the two facts above, answer the question "What prevents erosion on dunes?" with the following options: 
- streams
 - cacti
 - wind
 - LEDs
 - fibrous
 - grass
 - fibers
 - bamboo


 

      grass   