Spiny skinned animals with radial symmetry in adult and bilateral in larva belong to -

Options

A. Echinodermata
B. Arthropoda
C. Mollusca
D. Annelida

Answer

To solve the question about the classification of spiny-skinned animals with radial symmetry in adults and bilateral symmetry in larvae, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Key Characteristics**: The question mentions "spiny-skinned animals" and specifies that they exhibit "radial symmetry" in adults and "bilateral symmetry" in their larval stage.

2. **Recall Relevant Phyla**: We need to consider the characteristics of various animal phyla to find the one that matches these criteria. The options given are:
- Echinodermata
- Arthropoda
- Mollusca
- Annelida

3. **Analyze Each Option**:
- **Echinodermata**: This phylum includes animals like starfish and sea urchins, which are known for their spiny skin. They exhibit radial symmetry as adults and bilateral symmetry in their larval stages.
- **Arthropoda**: This phylum includes insects, arachnids, and crustaceans, which do not have spiny skin and do not fit the symmetry criteria.
- **Mollusca**: This phylum includes snails and octopuses, which do not have spiny skin and also do not fit the symmetry criteria.
- **Annelida**: This phylum includes segmented worms, which also do not have spiny skin and do not fit the symmetry criteria.

4. **Confirm the Correct Phylum**: Based on the analysis, Echinodermata is the only phylum that fits all the criteria mentioned in the question.

5. **Conclusion**: Therefore, the answer to the question is that spiny-skinned animals with radial symmetry in adults and bilateral symmetry in larvae belong to the phylum **Echinodermata**.

### Final Answer:
**Echinodermata**