A vertebrate having entire cartilaginous sleleton is

Options

A. Scoliodon
B. Rana
C. Labeo
D. Dolphin

Answer

To solve the question "A vertebrate having entire cartilaginous skeleton is," we need to analyze the options provided: Scoliodon, Rana, Labio, and Dolphin.

### Step-by-Step Solution:

1. **Identify the Options**:
- Scoliodon
- Rana
- Labio
- Dolphin

2. **Analyze Each Option**:
- **Scoliodon**: This is commonly known as dogfish. It belongs to the class Chondrichthyes, which is characterized by having a cartilaginous skeleton.
- **Rana**: This is known as the pond frog. Frogs belong to the class Amphibia, which has a bony skeleton.
- **Labio**: This refers to carp fish, which belongs to the class Osteichthyes. Osteichthyes are known for their bony skeletons.
- **Dolphin**: Dolphins are aquatic mammals and belong to the class Mammalia, characterized by having a bony skeleton.

3. **Conclusion**:
- Among the options, only Scoliodon (dogfish) has an entire cartilaginous skeleton. Therefore, the correct answer is **Scoliodon**.

### Final Answer:
The vertebrate having an entire cartilaginous skeleton is **Scoliodon**.