In angiosperms the functional megaspore in the linear tetrad is generally

Options

A. Micropylar
B. Second from micropylar
C. Third from micropylar
D. Fourth from micropylar.

Answer

To solve the question about the functional megaspore in the linear tetrad of angiosperms, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Megaspore Mother Cell (MMC)**:
- In angiosperms, the process begins with the megaspore mother cell (MMC), which is diploid (2n).
- The MMC undergoes meiosis to produce four haploid (n) megaspores.

2. **Formation of Megaspores**:
- After meiosis, the four haploid megaspores are arranged in a linear tetrad.
- These megaspores are genetically identical but will have different fates.

3. **Degeneration of Megaspores**:
- Out of the four megaspores formed, typically three of them degenerate.
- The megaspores that degenerate are usually the ones that are closer to the micropyle (the opening of the ovule).

4. **Identification of the Functional Megaspore**:
- The remaining megaspore, which is the one that is farthest from the micropyle, survives and develops into the functional megaspore.
- This functional megaspore will eventually undergo mitotic divisions to form the embryo sac.

5. **Conclusion**:
- Therefore, in angiosperms, the functional megaspore in the linear tetrad is generally the one that is farthest from the micropyle.

### Final Answer:
The functional megaspore in the linear tetrad of angiosperms is generally the fourth megaspore, which is farthest from the micropyle.

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