Which of the following combinations correctly matches a phylum to its description?

a. echinodermata - bilateral symmetry as a larva, water vascular system
b. nematoda - segmented worms, closed circulatory
c. cnidaria - flatworms, gastrovascular cavity, acoelomate
d. platyhelminthes - radial symmetry, polyp and medusa body forms

The answer is B

The phylum Nematoda (roundworms) is one of the most common phyla.

There more than 15,000 known species of roundworms, however, there are many thousands of individual varieties nematodes, as well.

a. decomposes use carbon from dead organisms as fuel for cellular respiration, returning carbon dioxide back into the atmosphere.

bc blah

explanation:

bc blah