EVERYDAY SCIENCE

Detailed explanation-1: -cephalopod, any member of the class Cephalopoda of the phylum Mollusca, a small group of highly advanced and organized, exclusively marine animals. The octopus, squid, cuttlefish, and chambered nautilus are familiar representatives.

Detailed explanation-2: -A cephalopod is an animal belonging to the group Cephalopoda, containing octopus, squid, cuttlefish, nautilus, and kin. The word “cephalopod” is derived from Greek and means “head foot, ” which perfectly describes animals that have eyes just above their many limbs.

Detailed explanation-3: -Cephalopods became dominant during the Ordovician period, represented by primitive nautiloids. The class now contains two, only distantly related, extant subclasses: Coleoidea, which includes octopuses, squid, and cuttlefish; and Nautiloidea, represented by Nautilus and Allonautilus.

Detailed explanation-4: -Excretory system – Cephalopods possess a single pair of large nephridia which produce nitrogenous waste and excrete it out from the body. Therefore, from the above discussion it has been clear that Sea squirt is not a cephalopod. Hence, option B is the correct answer.