Which one of the following statements about all the four of Spongilla, Leech, Dolphin and Penguin is correct?

Options

(a) Penguin is homeothermic while the remaining three are poikilothermic
(b) Leech is a fresh water 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

Correct Answer:

Spongilla has special collared cells called choanocytes, not found in the remaining three

Explanation:

Spongilla is a fresh water sponge that belongs to phylum porifera. It has special collared cells called choanocytes. Choanocytes are not found in leech, dolphin and penguin.