The ploidy level of secondary nucleus of embryosac is :-

Options

A. 2n
B. 3n
C. 4n
D. 5n

Answer

To determine the ploidy level of the secondary nucleus of the embryo sac, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Embryo Sac**:
- The embryo sac is the female gametophyte in flowering plants. It is found within the ovule and plays a crucial role in reproduction.

2. **Identifying the Components**:
- The embryo sac contains several types of cells, including antipodal cells, synergids, and the central cell which contains the secondary nucleus.

3. **Focusing on the Central Cell**:
- The central cell of the embryo sac is significant because it contains two polar nuclei. These nuclei are crucial for fertilization.

4. **Fusion of Polar Nuclei**:
- The two polar nuclei in the central cell fuse to form a single nucleus known as the secondary nucleus.

5. **Determining the Ploidy Level**:
- Since each polar nucleus is haploid (n), when they fuse, the resulting secondary nucleus becomes diploid (2n). This is because the fusion of two haploid nuclei results in a diploid nucleus.

6. **Conclusion**:
- Therefore, the ploidy level of the secondary nucleus in the embryo sac is diploid (2n).

### Final Answer:
The ploidy level of the secondary nucleus of the embryo sac is diploid (2n).

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