You are presented with the question "What helps soil to form?" and the following answer choices: 
- The planting of flowers
 - The breakdown of rocks
 - organic molecules
 - The changing of seasons
 - Organic compounds
 - swamp vegetation
 - evaporation
 - The movement of clouds

Now knowing that soil is formed by weathering and rocks breakdown by weathering, choose the best answer.


 

  The breakdown of rocks       