Question

Octopus, Squid and Cuttlefish belong to class
A. Cephalopoda
B. Apoda
C. Decapoda
D. Scaphopoda

Answer 1

Hint: Mollusca is the second largest phylum of invertebrate which comprises the classes cephalopoda, Decapoda, Scaphopoda. These classes are divided in accordance with the presence or absence, types of shells they have.

Complete Answer:
To solve this question, we must know about the different classes of Mollusca.
- Molluscs are soft bodied organisms that have a definite head and foot. Their body is covered with a hard exoskeleton. They are mostly herbivores which feed on algae and other aquatic flora. On the basis of exoskeleton, the phylum is divided into
- Cephalopoda have broad muscular feet with presence of definite shell. The organisms belonging to this class are octopus, squid, cuttlefish, and snail.
- Apoda is a class of amphibians.
- Decapoda is an order belonging to phylum Arthopoda.
- Scaphopoda have curved hollow and cylindrical shells which resemble tusks.

Thus the correct answer is (A). Octopus, Squid and Cuttlefish belong to class Cephalopoda.

Additional Information: Squid, cuttlefish and octopus are the neurologically most advanced among all invertebrates. The largest invertebrate found is an adult giant squid. A colossal squid recently discovered is around 500kg.

Note: The other classes of mollusc include gastropoda, bivalves, placophora. More than 2lakh species of mollusca exist in the living world. Mollusc serves as an important source of food for humans. Molluscs provide various valuable goods like pearls, tyrian purple dye, sea silk. Some of the species produce toxins which are hazardous for human life. Certain molluscs are used as bioindicators to monitor the health of aquatic environments.