Roundworms make up the phylum Nematoda, and also, nematoda and rotifera are important groups contributing to soils. Given these facts, _ contribute to soils. among the following options:
- Sediment
 - Aphids
 - cacti
 - Roundworms
 - Exfoliation
 - Amphibians
 - Ringworms
 - rainfall


 

    Roundworms     