Embryo sac is monosporic when it develops from

Options

A. One of the four megaspores of a megaspore mother cell
B. Three megaspores of a megaspore tetrad
C. Two functional megaspores
D. The megaspore mother cell where meiosis has occurred but cytokinesis does not take place.

Answer

To solve the question "Embryo sac is monosporic when it develops from," we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Source of the Embryo Sac**: The embryo sac develops from a structure known as the megaspore mother cell (MMC).

2. **Understand the Process of Megasporogenesis**: The megaspore mother cell undergoes meiosis, which is a type of cell division that reduces the chromosome number by half. This process results in the formation of four megaspores.

3. **Determine the Fate of the Megaspores**: Out of the four megaspores produced, only one megaspore is functional. The other three megaspores degenerate and do not contribute to the formation of the embryo sac.

4. **Define Monosporic Development**: Since the embryo sac develops from only one functional megaspore, this type of development is termed "monosporic."

5. **Conclude the Answer**: Therefore, the embryo sac is monosporic when it develops from one of the four megaspores of a megaspore mother cell.

### Final Answer:
The embryo sac is monosporic when it develops from one of the four megaspores of a megaspore mother cell.

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