Which one of the following statements about all the four of Spongilla, leech, dophin and penguin is correct ?

Options

A. Penguin is homiothermic, while the remaining three are poikilothermic
B. Leech is a freshwater form, while all others are marine
C. Spongilla has special collared cells called choanocytes, not found in the remaining three
D. All are bilaterally symmetrical

Answer

C

Explanation

Spongilla belongs to phylum-Porifera, in which, choanocytes are the characteristic cells, these are absent in leech,dolphin and pengiun. 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 the choanocytes are the primary areas where nutrients are absorbed into the sponge.