When a embryo sac develop from a single megaspore called monosporic development

Answer

**Step-by-Step Solution:**

1. **Understanding Megaspore**: The megaspore is the female reproductive unit in flowering plants. It is crucial for the development of the embryo sac.

2. **Formation of Megaspores**: The megaspore mother cell undergoes meiosis, which results in the formation of a tetrad of four haploid megaspores. This process is essential for sexual reproduction in plants.

3. **Degeneration of Megaspores**: Out of the four megaspores formed, typically three megaspores degenerate. The megaspore that remains functional is located at the chalazal end of the tetrad.

4. **Development of the Embryo Sac**: The functional megaspore undergoes a series of mitotic divisions. Initially, it divides to form two nuclei, then four nuclei, and finally eight nuclei.

5. **Arrangement of Nuclei**: The eight nuclei arrange themselves into specific groups to form the embryo sac. This includes the formation of antipodal cells, synergids, and the egg cell.

6. **Conclusion**: Since the embryo sac develops from a single megaspore, this process is termed "monosporic development." This indicates that one megaspore is responsible for the entire formation of the embryo sac.

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