Snakes and lizards shed their scales as skin cast it is

Options

A. Dermis
B. Epidermis
C. Cornified cells
D. Stratum germinativum

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question states that snakes and lizards shed their scales as skin cast. We need to identify the process and the type of cells involved in this shedding.

2. **Identify the Type of Animals**: Snakes and lizards belong to the class Reptilia, which is characterized by certain features, including their skin structure.

3. **Skin Structure in Reptiles**: The skin of reptiles, including snakes and lizards, consists of two main layers: the dermis (inner layer) and the epidermis (outer layer). The epidermis is made up of specialized cells.

4. **Specialized Cells in the Epidermis**: The epidermis in reptiles is composed of cornified cells. These cells are keratinized, meaning they are tough and provide protection.

5. **Process of Shedding**: The process by which snakes and lizards shed their scales is known as "ecdysis." During this process, the cornified cells are shed in a continuous layer, resulting in the shedding of scales.

6. **Frequency of Shedding**: Snakes and lizards typically shed their skin 8 to 12 times a year, which is different from humans who shed skin cells continuously.

7. **Conclusion**: The correct answer to the question is that snakes and lizards shed their scales as skin cast due to the presence of cornified cells in their epidermis, and this process is called ecdysis.

### Final Answer:
Snakes and lizards shed their scales as skin cast due to the presence of cornified cells in their epidermis, and this process is known as ecdysis.

---