B. Roundworms<span>.
The Protostome organisms are subclustered into three main groups,
moreover nematoda or roundworms belongs to the Ecdysozoa group.</span>
<span>Roundworms are organisms that are diverse and almost in clustered to many other ecosystems and environment.
These
Protostome includes mollusks, annelids, and arthropods
</span>
The type of evolutionary mechanism that occurred was natural selection