Question

Which one of the following groups of three animals each is correctly matched with their one characteristic morphological feature?
$\begin{array}{cc}\text{Animals}& \text{Morphological feature}\\ \text{A. Liver fluke, sea anemone,}& \text{Bilateral symmetry}\\ \text{sea cucumber}& \\ \text{B. Centipede, prawn, sea urchin}& \text{Jointed appendages}\\ \text{C. Scorpion, spider, cockroach}& \text{Ventral solid nerve cord}\\ \text{D. Cockroach, locust, Taenia}& \text{Metameric segmentation}\end{array}$

• A. A
• B. B
• C. C
• D. D

Answer 1

The correct option is C C

Scorpion, spider and cockroach belong to the phylum Arthropoda, and have a ventral solid nerve cord. Liver fluke (a flatworm) is bilaterally symmetrical. Sea anemone (a cnidarian) and sea cucumber (an echinoderm) are radially symmetrical. Jointed appendages are characteristic of arthropods and hence, sea urchin (an echinoderm) would not possess them. Metameric segmentation starts with Phylum Annelida, and is present in most higher phyla. Taenia is a flatworm, and does not exhibit metameric segmentation, although the body appears so. Segments of the tapeworm (proglottids) are formed so differently from the segments of groups like Annelids that most zoologists do not admit tapeworms to be metamerically segmented animals.