Which of the following animal is radially symmetrical but has a bilaterally symmetrical larva.

Options

A. Ascaris (Round worm)
B. Nereis (Ring worm)
C. Pila (Apple snail)
D. Asterias (Star fish)

Answer

To solve the question "Which of the following animal is radially symmetrical but has a bilaterally symmetrical larva?", we can follow these steps:

### Step 1: Understand the Definitions
- **Radial Symmetry**: An organism is radially symmetrical if it can be divided into similar halves by multiple planes passing through a central axis. Examples include jellyfish and sea stars.
- **Bilateral Symmetry**: An organism is bilaterally symmetrical if it can be divided into two identical halves along one plane, typically the left and right sides. Examples include humans and most animals.

### Step 2: Analyze the Given Options
1. **Ascaris (Roundworm)**: This organism exhibits bilateral symmetry throughout its life cycle, including its larval stage.
2. **Ringworm**: This is a fungal infection and not an animal, but if we consider the term in a biological context, it typically refers to organisms that also exhibit bilateral symmetry.
3. **Apple Snail**: This organism also shows bilateral symmetry in both adult and larval stages.
4. **Asterias (Starfish)**: This organism exhibits radial symmetry as an adult but has a bilaterally symmetrical larval stage.

### Step 3: Identify the Correct Answer
From the analysis, the only organism that fits the criteria of being radially symmetrical as an adult but having a bilaterally symmetrical larva is **Asterias (Starfish)**.

### Conclusion
The correct answer is **Option 4: Asterias**.

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