Choose the false statement about coelenterates.a)Cnidoblasts are used...
In coelenterates, skeletal system is absent except anthozoans or corals which have a calcium carbonate skeleton known as corallite.
Choose the false statement about coelenterates.a)Cnidoblasts are used...
False Statement about Coelenterates:
Explanation:
Coelenterates are a group of simple, aquatic organisms belonging to the phylum Cnidaria. They include organisms such as jellyfish, sea anemones, and corals.
Statement a) Cnidoblasts are used for anchorage, defense, and for the capture of prey:
Cnidoblasts, also known as cnidocytes, are specialized cells found in the tentacles of coelenterates. They contain stinging structures called nematocysts, which are used for defense and capturing prey. When triggered by touch or chemical stimuli, the nematocysts discharge a harpoon-like structure, injecting venom into the prey or predator. This statement is true.
Statement b) Corals have a predominantly siliceous skeleton:
Corals are sessile marine invertebrates that belong to the class Anthozoa within the phylum Cnidaria. They have a calcium carbonate skeleton, not a siliceous one. Corals extract calcium and carbonate ions from the surrounding water to build their skeletons, which form the basis of coral reefs. This statement is false.
Statement c) Polyp is a sessile and cylindrical form like Adamsia:
Polyps are the attached, sedentary form of coelenterates. They have a cylindrical body with a mouth surrounded by tentacles at the oral end. Adamsia, commonly known as the sea anemone, is an example of a polyp. It is attached to substrates and feeds on small organisms that come in contact with its tentacles. This statement is true.
Statement d) Medusa is an umbrella-shaped and free-swimming form like Aurelia:
Medusae are the free-swimming form of coelenterates. They have a bell-shaped or umbrella-shaped body with tentacles hanging down from the edge. Aurelia, commonly known as the moon jellyfish, is an example of a medusa. It moves by pulsations of its bell-shaped body and captures prey using its tentacles. This statement is true.
In conclusion, the false statement about coelenterates is option 'b' - Corals have a predominantly siliceous skeleton.
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