Which of the following pair is unmatched for the animals of Reptilia class:-

Options

A. Temperature constant and external fertilisation
B. Sexes seperate and lack of Metamorphosis
C. 12 pairs cranial nerves and skin rough
D. Skull monocondylic and skin with scales

Answer

To determine which pair is unmatched for the animals of the Reptilia class, we need to analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understand the Characteristics of Reptilia**:
- Reptiles are cold-blooded (ectothermic) animals.
- They usually have dry skin covered with scales.
- Most reptiles lay eggs with internal fertilization.

2. **Analyze Each Option**:
- **Option 1: Temperature constant and external fertilization**:
- Reptiles do not maintain a constant body temperature as they are ectothermic.
- They also typically exhibit internal fertilization rather than external.
- Therefore, this pair is unmatched.

- **Option 2: Sex is separate and lack of metamorphosis**:
- Reptiles have separate sexes (dioecious) and do not undergo metamorphosis like amphibians.
- This pair is matched.

- **Option 3: 12 pair cranial nerves and skin is shown as rough**:
- Reptiles have 12 pairs of cranial nerves, and their skin is indeed rough due to the presence of scales.
- This pair is matched.

- **Option 4: Skull is monocondylic and skin with scales**:
- Reptiles have a monocondylic skull (one occipital condyle) and their skin is covered with scales.
- This pair is matched.

3. **Conclusion**:
- The unmatched pair for the animals of the Reptilia class is **Option 1: Temperature constant and external fertilization**.

### Final Answer:
The unmatched pair for the animals of the Reptilia class is **Option 1: Temperature constant and external fertilization**.