One trait that is shared by humans and protostomes is __________.

What is a lophophore?

a. A specialized filter-feeding structure

b. The single opening in species with a blind gut

c. A distinctive type of larva with a band of cilia

d. A synapomorphy that defines lophotrochozoans

Brachiopoda is a phylum within the Lophotrochozoa. Even though they are not closely related to bivalve mollusks (such as clams or mussels), brachiopods look and act like bivalve mollusks. Specifically, brachiopods suspension feed, secrete calcium carbonate shells with two valves that hinge together in some species, and attach to rocks or other hard surfaces on the ocean floor. How is it possible for brachiopods and bivalves to be so similar if they did not share a recent common ancestor?