Secondary nucleus formed by the fusion of two polar nuclei is also called

Options

A. Vegetative nucleus
B. Definitive nucleus
C. Generative nucleus
D. Primary endosperm nucleus.

Answer

To solve the question "Secondary nucleus formed by the fusion of two polar nuclei is also called," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- The secondary nucleus is formed during the process of double fertilization in flowering plants. It is created by the fusion of two polar nuclei found in the embryo sac.

2. **Identifying the Options**:
- The question provides four options:
a) Vegetative nucleus
b) Definitive nucleus
c) Generative nucleus
d) Primary endosperm nucleus

3. **Analyzing Each Option**:
- **Option a: Vegetative nucleus**: This is present in the young pollen grain and is not related to the fusion of polar nuclei. Therefore, this option is incorrect.
- **Option b: Definitive nucleus**: This term is often used to refer to the secondary nucleus formed by the fusion of the two polar nuclei. This option appears to be correct.
- **Option c: Generative nucleus**: This is also found in the young pollen grain and is responsible for forming male gametes. Thus, this option is incorrect.
- **Option d: Primary endosperm nucleus**: This is formed by the fusion of a male gamete with the diploid secondary nucleus, making this option incorrect as well.

4. **Conclusion**:
- After analyzing all the options, the correct answer is **b) Definitive nucleus**, as it is the term used for the secondary nucleus formed by the fusion of two polar nuclei.

### Final Answer:
The secondary nucleus formed by the fusion of two polar nuclei is also called the **Definitive nucleus**.

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