Which one of the following is a matching set of the class and some of its main distinguishing features, classification, and examples?

Options

A. Cyclostomata - Division Agnatha, 6- 15 pairs of gill slits, endoskeleton bony, Example: Myxine
B. Reptilia - Division Gnathostomata, epidermal scutes, endoskeleton body, Example: Hemidactylus
C. Amphibia - Super-class Tetrapoda, cloaca as a common opening for the alimentary canal and urinary tract
D. Chondrichthyes - Super-class Pisces, gill slits without operculum, exoskeleton cartilaginous, Example: Carcharodon

Answer

To solve the question regarding the matching set of the class and its distinguishing features, classification, and examples, we will analyze each option provided. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Classification
- The question involves classes within the subphylum Vertebrata, which is divided into two main divisions:
- **Agnatha**: Jawless vertebrates (e.g., Cyclostoma)
- **Gnathostoma**: Jawed vertebrates (e.g., Reptilia, Amphibia, Chondrichthyes, etc.)

### Step 2: Analyze Each Option
1. **Cyclostoma**:
- Classification: Belongs to Agnatha.
- Distinguishing Features: Typically have 6 to 15 pairs of gill slits.
- Example: Hagfish (Myxine) and Lamprey (Petromyzon).
- **Evaluation**: The statement about having a bony endoskeleton is incorrect; they have a cartilaginous endoskeleton. Thus, this option is **incorrect**.

2. **Reptilia**:
- Classification: Belongs to Gnathostoma.
- Distinguishing Features: Have epidermal scales and a bony endoskeleton.
- Example: Wall Lizard (Amydactylus).
- **Evaluation**: All statements are correct. Thus, this option is **correct**.

3. **Amphibia**:
- Classification: Belongs to Tetrapoda.
- Distinguishing Features: Have a cloaca (common opening for excretory and reproductive systems).
- Example: Frogs, toads, etc.
- **Evaluation**: The statement regarding the cloaca is misleading as it does not specify that it also serves the urinary tract. Thus, this option is **incorrect**.

4. **Chondrichthyes**:
- Classification: Belongs to the superclass Pisces.
- Distinguishing Features: Have gill slits without operculum and a cartilaginous endoskeleton.
- Example: Sharks and rays.
- **Evaluation**: The statement regarding the exoskeleton is incorrect; they have an endoskeleton. Thus, this option is **incorrect**.

### Conclusion
Based on the evaluations, the only correct matching set is **Option 2: Reptilia**.

### Final Answer:
**Option 2: Reptilia - Correct**

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