Which one of the following statements about all the four of Spongilla, leech, dolphin and penguin is correct ?
(a) Penguin is homiothermic while the remaining three are poikilothermic
(b) Leech is fresh water from while all others are marine
(c) Spongilla has special collared cells called choanocytes, not found in the remaining three
(d) All are bilaterlly symmetrical

Options

A. Penguin is homoiothermic while the remaining three are poikilothermic
B. Leech is fresh water from while all others are marined
C. Spongilla has special collared cells called choanocytes, not found in the remaining three
D. All are bilaterlly symmetrical

Answer

To solve the question regarding the statements about Spongilla, leech, dolphin, and penguin, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Option (a): Penguin is homiothermic while the remaining three are poikilothermic.**
- Penguins are indeed homiothermic (warm-blooded), but leeches and Spongilla can be found in freshwater environments and are not classified as poikilothermic in the same way as reptiles or fish. This statement is partially true but does not accurately represent all four organisms.

2. **Option (b): Leech is freshwater while all others are marine.**
- Leeches are primarily freshwater organisms, while Spongilla can be found in both freshwater and marine environments. Dolphins and penguins are marine animals. Thus, this statement is incorrect as it generalizes the habitat of Spongilla.

3. **Option (c): Spongilla has special collared cells called choanocytes, not found in the remaining three.**
- Spongilla, which is a type of sponge, does have choanocytes, which are specialized cells that help in feeding. However, choanocytes are characteristic of all sponges, not just Spongilla. Therefore, this statement is misleading.

4. **Option (d): All are bilaterally symmetrical.**
- Spongilla is asymmetrical or exhibits radial symmetry, while leeches, dolphins, and penguins are bilaterally symmetrical. Therefore, this statement is incorrect.

### Conclusion:
After evaluating all the options, none of the statements are entirely correct. However, the closest correct statement is option (a), as it correctly identifies penguins as homiothermic, though it inaccurately categorizes the other three organisms.

### Final Answer:
None of the statements are fully correct, but option (a) is the most accurate regarding the classification of penguins.