Unpaired external naris occurs in

Options

A. Petromyzon
B. Torpedo
C. Anabas
D. Solea

Answer

To determine which organism has an unpaired external naris, we can follow these steps:

1. **Understand the Question**: The question asks which of the given organisms has a single external nostril, also known as an unpaired external naris.

2. **Analyze the Options**: The options provided are:
- A) Petromyson (Vampire fish)
- B) Torpedo
- C) Anabas
- D) Solia

3. **Research Each Option**:
- **Petromyson (Vampire fish)**: This fish is known to have a single external nostril located on the dorsal side of its body.
- **Torpedo**: This organism typically has paired nostrils.
- **Anabas**: This fish also has paired nostrils.
- **Solia**: Similar to the others, this fish has paired nostrils.

4. **Identify the Correct Answer**: Based on the analysis, Petromyson is the only organism listed that has an unpaired external naris.

5. **Conclusion**: The correct answer to the question is option A, Petromyson.