Question

17. Describe the symmetry of Pelecypods. 18. What is unique about the internal shell of the Cephalopod? 19. What kind of environment are Trilobites found in? 20. What type of symmetry is unique to the Echinoderms? RYZEN 21. What are the most common and distinctive features of the stalked Echinoderms? 22. In addition to the Crinoid, which is the other major group of stalked echinoderms? 23. What are the more common fossil unstalked Echinoderms called? 24. What properties characterize the vertebrate animals? 25. What sedimentary rock is composed of partially decomposed plant materials?

Answer 1

Answer - 17)

Pelecypods are a type of mollusk that has 2 shells and these shells can be closed by adductor muscles

Pelecypods have symmetry known as bivalve symmetry. That is top and lower part of Pelecypods are mirror images to each other.

In other words we can say that Pelecypods has a symmetry along a hinge line.

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