Question

Nematocysts are found in
A) Porifera
B) Coelenterata
C) Nematodes
D) Annelida

Answer 1

Hint: Nematocysts are specialized, characteristic organs for anchorage, defense, and capturing the prey. Nematocysts are cells that contain poison, that stings to the prey and deliver the poison by a thread-like tubule in the prey. This feature is to capture the prey and subdue it.

Complete Answer:
- The nematocysts of cnidoblasts also termed as cnidocytes are the characteristic feature of the members of the phylum Coelenterata.
- The phylum Porifera, Annelida, and Nematoda do not possess nematocysts. The members of the phylum Porifera have spicules for the skeleton as the characteristic features of phylum Porifera. Generally,these are also marine organisms. They have an asymmetrical body.
- The annelids have ring-like segments present on their body as their diagnostic feature. These are also called round-worms. These are cylindrical with the tissue-level organization.

So ‘Coelenterata’ is the correct answer.

Additional information: Coelenterata is a phylum of the kingdom of Animalia. It is also known as the simplest phylum of the animal group.
- Coelenterates are multicellular, aquatic, mostly marine organisms that survive in the colonies. They have tissue level organization, with radial symmetry.
- The respiratory, circulatory, and excretory systems are not found in members of this phylum. Respiration and Excretion take place through the general body surface.

Note:Coelenterates are classified further into three different classes on the basis of the development of zooids: Anthozoa. Hydrozoa and Scyphozoa.
- The example of coelenterates are jellyfish, coral animals, and sea anemones.
- The term coelenterate was coined by Leuckart in 1847.