Wheel organ is found in :-

Options

A. Herdmania
B. Amphioxus
C. Balanoglossus
D. All the above

Answer

To determine where the wheel organ is found, we can analyze the options provided step by step.

### Step-by-Step Solution:

1. **Identify the Options**: The question asks where the wheel organ is found, and we have the following options:
- A) Herdmania
- B) Amphioxus
- C) Planoglossus
- D) All of the above

2. **Analyze Option A - Herdmania**:
- Herdmania is a type of tunicate (a marine invertebrate) that undergoes retrogressive metamorphosis. In this process, the larval form is more complex than the adult form. Since the wheel organ is not associated with Herdmania, this option is incorrect.

**Hint**: Consider the life cycle and complexity of the organism when determining the presence of specific structures.

3. **Analyze Option B - Amphioxus**:
- Amphioxus, also known as lancelets, is a primitive chordate. The wheel organ, which is a ciliated structure used for feeding, is indeed found in Amphioxus. Therefore, this option is correct.

**Hint**: Look for structures that are associated with feeding and locomotion in primitive chordates.

4. **Analyze Option C - Planoglossus**:
- Planoglossus is a type of flatworm (specifically, a turbellarian). It does not possess a wheel organ. Therefore, this option is incorrect.

**Hint**: Identify the classification of the organism to determine the presence of specific anatomical features.

5. **Analyze Option D - All of the above**:
- Since we have already established that only Amphioxus contains the wheel organ, this option is also incorrect as it implies that all listed organisms have it.

**Hint**: Consider the exclusivity of anatomical features when evaluating options that suggest multiple organisms share a characteristic.

### Final Answer:
The wheel organ is found in **Amphioxus** (Option B).