NEET BIOLOGY

Detailed explanation-1: -The phylum Mollusca is the second-largest animal phylum, with over 100, 000 species. The molluscs include many familiar animals, including clams, snails, slugs, and squid, as well as some less familiar animals, like tusk shells and chitons (Fig. 3.51 A).

Detailed explanation-2: -Mollusca is one of the most diverse groups of animals on the planet, with at least 50, 000 living species (and more likely around 200, 000). It includes such familiar organisms as snails, octopuses, squid, clams, scallops, oysters, and chitons.

Detailed explanation-3: -Cephalopods are a group of molluscs that include the pearly chambered Nautilus, squids, and the octopus. They can be divided into three categories: the Nautiloidea (chambered Nautilus), the Ammonoidea (the extinct ammonites), and the Dibranchiata (squids, the extinct belemnites, and octopuses).

Detailed explanation-4: -The three main groups of mollusks are bivalves, gastropods, and cephalopods. 4. What are the four major mollusks? They are gastropods, bivalves, cephalopods, and scaphopods.

Detailed explanation-5: -The Class Gastropoda (in Phylum Mollusca) includes the groups pertaining to snails and slugs. The majority of gastropods have a single, usually spirally, coiled shell into which the body can be withdrawn. The shell of these creatures is often what is recovered in a fossil dig.