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

Fact 2: Vegetation stabilizes the sand, preventing the wind from forming dunes.

Given the two facts above, answer the question "What will prevent the formation of sand dunes?" with the following options: 
- focusing a lens
 - forces
 - energy barrier
 - flooding
 - erosion
 - less water
 - Solar energy
 - vegetation


 

        vegetation 