Secondary nucleus is formed by

Options

A. Egg apparatus
B. Fusion of two polar nuclei
C. degenerating synergid
D. Antipodal cells.

Answer

To answer the question "Secondary nucleus is formed by," we can follow these steps:

### Step 1: Understand the Components Involved
The secondary nucleus is formed within the female gametophyte, specifically in the central cell of the embryo sac. It is important to identify the components involved in its formation.

**Hint:** Consider the structure of the embryo sac and the types of nuclei present.

### Step 2: Identify the Nuclei in the Central Cell
In the central cell of the embryo sac, there are typically two polar nuclei. These nuclei are crucial for the formation of the secondary nucleus.

**Hint:** Recall the role of polar nuclei in the embryo sac.

### Step 3: Determine the Process of Formation
The secondary nucleus is formed by the fusion of these two polar nuclei. This fusion is a key event in the development of the embryo sac and is essential for subsequent fertilization processes.

**Hint:** Think about the term "fusion" and how it applies to the nuclei.

### Step 4: Confirm the Correct Option
Among the options provided, the correct answer is "fusion of two polar nuclei." The other options, such as egg apparatus, synergids, and antipodal cells, do not contribute to the formation of the secondary nucleus.

**Hint:** Eliminate options that do not involve the fusion of nuclei.

### Step 5: Understand the Significance
The secondary nucleus, also referred to as the definitive nucleus, plays a vital role in the development of the endosperm after fertilization. It is important to understand its function in the context of plant reproduction.

**Hint:** Consider the role of the secondary nucleus in the formation of endosperm.

### Final Answer
The secondary nucleus is formed by the fusion of two polar nuclei.

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