Question

Besides annelida and arthropoda, the metamerism is exhibited by

• A. mollusca
• B. acanthocephala
• C. cestoda
• D. chordata.

Answer 1

The Correct Option is D

The question asks about the presence of metamerism in various animal phyla, besides Annelida and Arthropoda. Let's explore the options to understand which other phylum exhibits metamerism:

1. Mollusca: This phylum primarily consists of animals like snails, octopuses, and clams. They exhibit a different type of body organization and do not show distinct segmental organization like metamerism.
2. Acanthocephala: These are parasitic worms known as thorny-headed worms. They do not exhibit metamerism as their bodies are not segmented distinctly.
3. Cestoda: This class includes tapeworms, which are parasitic. Though they have a "pseudo-segmented" appearance due to the proglottids, it is not true metamerism as observed in Annelida, Arthropoda, or Chordata.
4. Chordata: This phylum includes animals like fish, amphibians, reptiles, birds, and mammals. Members of this phylum do exhibit metamerism, especially in their embryonic development stages, where the body is segmented into somites, which later develop into the axial skeletal structures and associated musculature.

Thus, apart from Annelida and Arthropoda, the Chordata phylum exhibits metamerism.

The correct answer is chordata.