Which one of the following statement about all the four of Spongilla, Leech, Dolphin and Penguin is correct ?
- AAll are bilaterally symmetrical
- BPenguin is homoiothermic while the remaining three are poikilothermic
- CLeech is a fresh water form while all others are marine
- DSpongilla has special collar called choanocytes, not found in the remaining three.
✓ Correct answer: D
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