Which one of the following statements about all the four of Spongilla, leech, dolphin and penguin is correct?
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Penguin is homoiothermic while the remaining three are poikilothermic
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Leech is a fresh water from while all other are marine
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Spongilla has special collared cells called choanocytes, not found in the remaining three
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All are bilaterally symmetrical
C.
Spongilla has special collared cells called choanocytes, not found in the remaining three
Spongilla belongs to phylum- Porifera, in which, choanocytes are the characteristic cells, these are absent in leech, dolphin and penguin. These distinctive cells line the interior body walls of sponges. These cells have a central flagellum that is surrounded by a collar of microvilli Choanocytes are versatile cells. Their flagella beat to create the active pumping of water through the sponge, while the collars of choanocytes are the primary area where nutrients absorbed into the sponge.
