Fact 1: Earthworm burrows help aerate soil, which is also good for plants.

Fact 2: Earthworms and other soil organisms keep the soil healthy.

Given the two facts above, answer the question "what do organisms aerate?" with the following options: 
- magma
 - moles.
 - roots
 - Carbon
 - volcanoes
 - cell walls
 - soil
 - Crops


 

       soil  