You are presented with the question "aside from free-living, where else can roundworms exist?" and the following answer choices: 
- mouth of rivers
 - in the sky
 - loose soil
 - our planet
 - Earth orbiting the Sun
 - live off a host
 - molecules
 - h2o

Now knowing that roundworms may be free-living or parasitic and parasites are organisms that live off a host, choose the best answer.


 

      live off a host   