Question

One of the following is not an Annelid

• A. Nereis
• B. Earthworm
• C. Leech
• D. Urchins

Answer 1

The correct option is D

Urchins

The correct option is D.

Explanation of the correct option:

Option D:

1. Sea urchins are spiny sea creatures that are round and prickly like hedgehogs.
2. They belong to the Echinoderm phylum.
3. They have a star-like appearance and are spherical or elongated.
4. They are exclusively marine animals.
5. The organisms are spiny-skinned.
6. They exhibit organ system level of organization. Most members have a circulatory system as well as a digestive system.
7. They are triploblastic and have a coelomic cavity.
8. The skeleton is made up of calcium carbonate.
9. They have an open circulatory system.

Explanations of the incorrect options:

Option A:

1. Phylum Annelida is a very broad phylum belonging to the kingdom Animalia.
2. The Annelids are found in aquatic as well as terrestrial environments.
3. The Annelids are coelomate and triploblastic.
4. They exhibit organ system-level organization.
5. Their body is segmented.
6. They respire through their body surface.
7. Nephridia are the excretory organs.
8. They have a well-developed circulatory and digestive system.
9. Their body contains hemoglobin, which gives them a red color.
10. Regeneration is a very common characteristic of the Annelids.
11. Nereis belongs to Phylum Annelida.

Option B:

Earthworm belongs to Phylum Annelida.

Option C:

Leech belongs to Phylum Annelida.

Final answer: Urchins is not an Annelida.