The looseness of soil increases the amount of oxygen in that soil, and soil oxygen effects on root development. Given these facts, why does it help for dirt to be loose among the following options:
- Physical weathering
 - adding heat
 - It used to be covered by water
 - permineralization
 - water conservation
 - Roots get more oxygen
 - The area was once underwater
 - Riding a bike


 

      Roots get more oxygen   