Give a brief account of Shell in mollusca

1.	Give a brief account of Shell in mollusca
Answer» Molluscais the second largestphylumofinvertebrateanimals. The members are known asmolluscsormollusk. Around 85,000extantspeciesof molluscs are recognized.The number of fossil species is estimated between 60,000 and 100,000 additional species.Molluscs are the largestmarinephylum, comprising about 23% of all the named marineorganisms. Numerous molluscs also live infreshwaterandterrestrialhabitats. They are highly diverse, not just in size and inanatomicalstructure, but also in behaviour and in habitat. The phylum is typically divided into 8 or 9taxonomicclasses, of which two are entirelyextinct.Cephalopodmolluscs, such assquid,cuttlefishandoctopus, are among the mostneurologically advancedof allinvertebrates—and either thegiant squidor thecolossal squidis the largest known invertebrate species. Thegastropods(snailsandslugs) are by far the most numerous molluscs and account for 80% of the total classified species.

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