They make the soil clean. They keep disease out of the soil. They recycle nutrients into the soil. They remove extra water from the soil.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which best describes how earthworms improve soil as they eat dead plant material?
Possibilities:
- They make the soil clean.
- They keep disease out of the soil.
- They recycle nutrients into the soil.
- They remove extra water from the soil.

They recycle nutrients into the soil.