The epithelial lining of respiratory system in frog is derived by

Options

A. Ectoderm
B. Endoderm
C. Mesoderm
D. Mesoderm and endoderrn

Answer

To determine the origin of the epithelial lining of the respiratory system in frogs, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Germ Layers**:
- In embryonic development, there are three primary germ layers: ectoderm, mesoderm, and endoderm. Each layer gives rise to different tissues and organs in the body.

2. **Identify the Functions of Each Germ Layer**:
- **Ectoderm**: This layer primarily forms the nervous system and the epidermis (outer skin layer).
- **Mesoderm**: This layer is responsible for forming muscle cells, connective tissues, and various internal organs.
- **Endoderm**: This layer gives rise to the gut and many internal organs, including the respiratory system.

3. **Focus on the Respiratory System**:
- The question specifically asks about the epithelial lining of the respiratory system. The respiratory system is classified as an internal organ.

4. **Determine the Correct Germ Layer**:
- Since the epithelial lining of the respiratory system is part of the internal organs, it is derived from the endoderm.

5. **Conclude the Answer**:
- Therefore, the epithelial lining of the respiratory system in frogs is derived from the **endoderm**.

### Final Answer:
The epithelial lining of the respiratory system in frogs is derived from the **endoderm**.

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