Roundworms make up the phylum nematoda.
Nematodes are microscopic roundworms.
Nematodes are microscopic worms that are apart of the phylum nematoda.
What phylum are Nematodes apart of?

a) the eyes
b) a cuticle
c) organ
d) Nematoda
e) graptolites
f) ferns
g) parasites
h) Length