Question

Octopus has 8 arms and it belongs to the class
(a)Cephalopoda
(b)Rhizopoda
(c)Gastropoda
(d)Pelecypoda

Answer 1

Hint: The octopus is a soft-bodied, 8-limbed mollusc of the class Octopoda (plural octopus). The order is grouped with squids, cuttlefish, and nautiloids, and about 300 species are recognized. The octopus is bilaterally symmetrical and its mouth is at the middle point of the eight limbs. The soft body can easily change its shape, making it possible for octopuses to fit through narrow gaps.

Complete answer:
A cephalopod, a squid, an octopus, a seedling, or a nautilus, for instance. A branch of malacology known as theuthology is the study of cephalopods. Fishermen, referring to their common ability to squirt ink, also call cephalopods "inkfish,"
During the Ordovician period, represented by primitive nautiloids, cephalopods became dominant. There are now two current subclasses in the class, only distantly related: Coleoidea, which includes octopuses, squid, and cuttlefish; and Nautiloidea, which is described by Nautilus and Allonautilus. The molluscan shell has been internalized or is absent in the Coleoidea, while the external shell stays in the Nautiloidea. It has described 800 living species of cephalopods.

Additional information:
In freshwater and marine environments and in the soil, rhizopods are found. By binary fission, the amoebas replicate, while the cellular slime moulds aggregate into a slimy mass that produces spores. See Amoeba, too; protozoa.
Within the phylum Mollusca, the gastropods, generally known as snails and slugs, belong to a broad taxonomic class of invertebrates called Gastropoda. Snails and slugs from saltwater, freshwater, and land compose this class. As well as freshwater snails, freshwater limpets, and ground snails and slugs, several thousands of species of sea snails and slugs occur.

So, the correct answer is ‘Cephalopoda’.

Note: Situated under the digestive gland is the ink sac of an octopus. The ink is produced by a gland attached to the sac, and the sac stores it. For the octopus to shoot out the ink with a water jet, the sac is close enough to the funnel. Melanin, which gives it a black color, is the main pigment in the dye.