Primary endosperm nucleus is formed by the fusion of _____ and_______

Options

A. Zygote and male gamete
B. Male gamete and embryo
C. Pollen grain and embryo
D. Secondary nuclie and male gamete

Answer

To answer the question "Primary endosperm nucleus is formed by the fusion of _____ and_______", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Primary Endosperm Nucleus (PEN)**:
- The primary endosperm nucleus is a crucial structure in the process of fertilization in flowering plants. It plays a significant role in the development of the endosperm, which nourishes the developing embryo.

2. **Identifying the Components Involved**:
- The primary endosperm nucleus is formed during the process of double fertilization, which is unique to angiosperms (flowering plants).
- In double fertilization, one male gamete fuses with the female gamete (egg cell) to form the zygote, while the other male gamete fuses with the polar nuclei.

3. **Defining the Polar Nuclei**:
- The polar nuclei are two nuclei found in the central cell of the ovule. They are also referred to as the secondary nuclei.

4. **Fusion Process**:
- The fusion of one male gamete with the two polar nuclei results in the formation of the primary endosperm nucleus.

5. **Final Answer**:
- Therefore, the primary endosperm nucleus is formed by the fusion of the **male gamete** and the **polar nuclei** (or secondary nuclei).

### Conclusion:
The correct answer to the question is: **Male gamete and polar nuclei**.