Which of the following statement is correct regarding sponges without any exception ?

Options

A. They all have calcareous spicules
B. They have high regenerative power
C. They are found only in arine habitat
D. They are all radially symmetrical

Answer

To determine which statement is correct regarding sponges without any exception, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Sponges**: Sponges are simple aquatic animals belonging to the phylum Porifera. They are known for their porous bodies and lack of true tissues.

2. **Analyzing the Options**:
- **Option 1**: "They all have calcareous spicules."
- **Evaluation**: This statement is incorrect. While some sponges do have calcareous spicules, not all sponges possess them. Many sponges have silica spicules or none at all.

- **Option 2**: "They have high regenerative power."
- **Evaluation**: This statement is correct. Sponges have remarkable regenerative abilities; they can regenerate from fragments and can even reform their entire body from small pieces.

- **Option 3**: "They are found only in marine habitat."
- **Evaluation**: This statement is incorrect. Sponges are found in both marine (saltwater) and freshwater environments, as well as on land in some cases.

- **Option 4**: "They are all radially symmetrical."
- **Evaluation**: This statement is incorrect. Sponges exhibit a variety of shapes and do not have a consistent radial symmetry; they can be asymmetrical or exhibit other forms of symmetry.

3. **Conclusion**: After evaluating all the options, the only correct statement regarding sponges without any exception is **Option 2: They have high regenerative power**.

### Final Answer:
The correct statement regarding sponges without any exception is: **They have high regenerative power.**