Roundworms make up the phylum nematoda.
Also, nematoda and rotifera are important groups contributing to soils.
Roundworms contribute to soils.
_ contribute to soils.
Options:
A: Sediment
B: Aphids
C: cacti
D: Roundworms
E: Exfoliation
F: Amphibians
G: Ringworms
H: rainfall