Which of the following statements is correct for sponges without exception?

Options

A. They all have calcareous spicules
B. They have high regenerative power
C. They are found only in marine water
D. They are all radially symmetric

Explanation

To determine which statement is correct for sponges without exception, we need to analyze the characteristics of sponges, which belong to the phylum Porifera.

### Step-by-Step Solution:

1. **Identify the Phylum**: Sponges belong to the phylum Porifera. This is the first key point to remember.

2. **Habitat**: Sponges can be found in both freshwater and marine environments. This indicates their adaptability to different aquatic habitats.

3. **Body Structure**: Sponges are known for their porous body structure. They have a body that is perforated with many small holes (pores), allowing water to flow through them.

4. **Symmetry**: Sponges are asymmetrical, meaning they do not have a definite shape or symmetry like many other animals. This characteristic is unique to sponges.

5. **Cellular Organization**: Sponges have a simple cellular organization and do not have true tissues or organs. They are made up of specialized cells that perform various functions.

6. **Regeneration**: Sponges have a high regenerative capacity. They can regenerate lost parts and can even reassemble from fragments.

7. **Conclusion**: Based on these characteristics, the statement that is correct for sponges without exception is that they are asymmetrical and have a porous body structure.

### Final Answer:
The correct statement for sponges without exception is that they are asymmetrical.

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