While sampling marine plankton in a lab, a student encounters large numbers of fertilized eggs. The student rears some of the eggs in the laboratory for further study and finds that the blastopore becomes the mouth. The embryo develops into a trochophore larva and eventually has a true coelom. These eggs probably belonged to a(n) ________.
A) echinoderm
B) mollusc
C) nematode
D) arthropod

Question

Quizplus · Accepted Answer

The development described is characteristic of molluscs, which have trochophore larvae and a protostome pattern of development, meaning the blastopore becomes the mouth. Echinoderms and arthropods have deuterostome patterns of development, while nematodes are typically free-living or parasitic worms with a different type of larval development.

While Sampling Marine Plankton in a Lab, a Student Encounters