If the looseness of dirt or compost has a positive impact on a plant's roots' growth, then what has a positive impact on a plant's roots' growth?

Answer choices:
- reducing acid rain
 - color of dirt
 - looseness of dirt or compost
 - basic building blocks of life
 - biological diversity
 - lead in the soil
 - Evaporation of water
 - a lack of soil

 

   looseness of dirt or compost       