Fact 1: Roundworms make up the phylum Nematoda. Fact 2: Nematodes are microscopic roundworms. Given the two facts above, what phylum are Nematodes apart of?

Choices:
i. the eyes;
ii. a cuticle;
iii. organ;
iv. Nematoda;
v. graptolites;
vi. ferns;
vii. parasites;
viii. Length;
The answer is:
iv.