A trpical embryo sac is

Options

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

Answer

### Step-by-Step Solution:

1. **Understanding the Embryo Sac Formation**:
- The embryo sac is formed from the megaspore mother cell through a process called megasporogenesis.

2. **Meiotic Division**:
- The megaspore mother cell undergoes meiotic division, resulting in the formation of four haploid megaspores.

3. **Selection of Functional Megaspore**:
- Out of the four megaspores produced, three degenerate, leaving only one functional megaspore.

4. **Mitosis of the Functional Megaspore**:
- The single functional megaspore undergoes mitotic divisions. Specifically, it divides three times.

5. **Formation of Nuclei**:
- After three rounds of mitosis, the embryo sac contains a total of 8 nuclei.

6. **Cell Organization**:
- These 8 nuclei organize into 7 cells, which include the egg apparatus and other necessary structures.

7. **Conclusion**:
- Therefore, a typical embryo sac is described as being **8-nucleated and 7-celled**.

### Final Answer:
A typical embryo sac is **8-nucleated and 7-celled**.

---