Question: Fact 1: Roundworms make up the phylum Nematoda.  Fact 2: Also, nematoda and rotifera are important groups contributing to soils.  Given the two facts above, answer the question "what contributes to soils?" with the following options:  - roundworms  - humans  - rainfall  - cacti  - bacteria  - weathering  - viruses  - Most plants
Answer:
roundworms