Answer:
trocophore larva
Step-by-step explanation:
The trocophore larva is a marine planktonic larvae. The mollusca, annelida, and nemerteans shows trocophore as larval stage.
The trocophore larva shows similarities with invertebrates group of organisms. This similarities provide evidence that bilateral symmetry organisms evolved from radial symmetry. The larva represents a transitional stage in ctenophore emergence. There are close similarities in trocophore larva and annelid larva (echinoderm). Thus, a close evolutionary relationship between annelids and mollusks is suggested by the presence of a trocophore larva in both phyla as well as by molecular sequence comparisons.