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

Options

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

Answer

D

Explanation

The characteristic feature of phylum porifera is the presence of choanocytes whose beating action creates water current