A typical embryo sac is

Options

A. 8-nucleated and 7-celled
B. 7-nucleated and 7-celled
C. 8-nucleated and 8-celled
D. 7-nucleated and 8-celled

Answer

**Step-by-Step Solution:**

1. **Understanding the Embryo Sac**: The embryo sac is the female gametophyte found in angiosperms (flowering plants). It plays a crucial role in reproduction.

2. **Components of the Embryo Sac**:
- The embryo sac typically contains:
- **Egg Apparatus**: This consists of one egg cell and two synergids (3 cells total).
- **Antipodal Cells**: There are three antipodal cells located at the chalazal end of the embryo sac.
- **Polar Nuclei**: There are two polar nuclei located in the center of the embryo sac.

3. **Counting the Cells**:
- From the egg apparatus, we have:
- 1 egg cell + 2 synergids = 3 cells
- From the antipodal cells, we have:
- 3 antipodal cells
- Total number of cells in the embryo sac:
- 3 (from egg apparatus) + 3 (antipodal cells) = 6 cells
- Additionally, we include the central cell which contains the polar nuclei, making it:
- 6 + 1 (central cell) = 7 cells

4. **Counting the Nuclei**:
- The nuclei in the embryo sac include:
- 3 nuclei from the antipodal cells (1 nucleus each)
- 2 nuclei from the synergids (1 nucleus each)
- 1 nucleus from the egg cell
- 2 polar nuclei that fuse to form a diploid secondary nucleus
- Total number of nuclei:
- 3 (antipodal) + 2 (synergids) + 1 (egg) + 2 (polar nuclei) = 8 nuclei

5. **Conclusion**: A typical embryo sac is 7 celled and 8 nucleated.

**Final Answer**: The correct option is **8 nucleated and 7 celled**.

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