Which one of the following is fibrous layer

Options

A. Middle layer
B. Endothecium
C. Tapetum
D. Endostomium.

Answer

To solve the question "Which one of the following is a fibrous layer?" we will analyze the options provided in the context of the layers of a microsporangium.

### Step-by-Step Solution:

1. **Understand the Context**: The question pertains to the layers of a microsporangium, which is a structure involved in the formation of pollen grains in plants.

2. **Identify the Layers**: A microsporangium typically has four layers:
- **Epidermis**: The outermost layer, which is non-fibrous and consists of living cells.
- **Endothasium**: The second layer, which is characterized by thickenings in its cell walls and is considered a fibrous layer.
- **Middle Layer**: The third layer, which consists of actively dividing cells and is non-fibrous.
- **Tapetum**: The innermost layer, which also consists of actively dividing cells and is non-fibrous.

3. **Analyze Each Option**:
- **Option 1: Midden Layer**: This is not a recognized layer in the context of microsporangium.
- **Option 2: Endothasium**: This layer has thickened walls and is classified as a fibrous layer.
- **Option 3: Tapetum**: This layer is involved in nourishing the developing pollen grains and is non-fibrous.
- **Option 4: Endosteum**: This is not relevant to the microsporangium layers.

4. **Conclusion**: Based on the analysis, the only fibrous layer among the options provided is the **Endothasium**.

### Final Answer:
The correct answer is **Option 2: Endothasium**.

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