Lungs alveoli of mammals have a thin wall composed of

Options

A. simple cuboidal epithelium
B. simple squamous epithelium
C. stratified cuboidal epithelium
D. stratified squamous epithelium

Answer

To answer the question "Lungs alveoli of mammals have a thin wall composed of," we need to analyze the options provided and identify the correct type of epithelial tissue.

### Step-by-Step Solution:

1. **Understanding Alveoli Structure**: The alveoli are tiny air sacs in the lungs where gas exchange occurs. Their structure is crucial for efficient diffusion of oxygen and carbon dioxide.

2. **Analyzing the Options**:
- **Simple Cuboidal Epithelium**: This type consists of a single layer of cube-shaped cells. It is primarily found in glandular tissues and does not facilitate gas exchange effectively.
- **Simple Squamous Epithelium**: This type consists of a single layer of flattened cells. It is thin and allows for easy diffusion of gases, making it ideal for the alveoli.
- **Stratified Cuboidal Epithelium**: This type consists of multiple layers of cube-shaped cells and is typically found in glands. It is not suited for gas exchange.
- **Stratified Squamous Epithelium**: This type has multiple layers of flattened cells and is designed for protection, not for gas exchange.

3. **Identifying the Correct Answer**: Given that the alveoli require a thin wall for optimal gas exchange, the correct answer is **Simple Squamous Epithelium** (Option B). This type of epithelium allows for the necessary permeability for gas diffusion.

4. **Conclusion**: The lungs' alveoli of mammals have a thin wall composed of **Simple Squamous Epithelium**, which is essential for the efficient exchange of gases.

### Final Answer:
**Option B: Simple Squamous Epithelium**

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