Fact 1: The looseness of soil increases the amount of oxygen in that soil.

Fact 2: Oxygen in the soil is vital for healthy roots.

Given the two facts above, answer the question "What in soil is vital for healthy roots?" with the following options: 
- looseness
 - nutrients
 - leftovers
 - compacted
 - ferns
 - cells
 - energy
 - trash


 

 looseness        