Fir st step in activation of ovum during process of fertilization is

Options

A. Formation of fertilization membrane
B. Fertilizin-antifertilizin reaction
C. Penetration of sperm in ovum
D. Formation of fertilization cone.

Answer

**Step-by-Step Solution:**

1. **Understanding Fertilization:** Fertilization is the process where a sperm cell unites with an ovum (egg cell) to form a zygote. This process involves several steps that lead to the activation of the ovum.

2. **Identifying the First Step:** The question asks for the first step in the activation of the ovum during fertilization. It is important to analyze the options provided.

3. **Analyzing the Options:**
- **Option a:** Formation of fertilization membrane.
- **Option b:** Fertilizing, anti-fertilizing reaction.
- **Option c:** Penetration of sperm in ovum.
- **Option d:** Formation of fertilization cone.

4. **Evaluating Each Option:**
- **Formation of fertilization membrane (Option a):** This occurs after the sperm has penetrated the ovum.
- **Fertilizing, anti-fertilizing reaction (Option b):** This is an immunological reaction where substances released from the ovum interact with the sperm, facilitating the entry of the sperm into the ovum.
- **Penetration of sperm in ovum (Option c):** This is a later step that occurs after the fertilizing and anti-fertilizing reaction.
- **Formation of fertilization cone (Option d):** This occurs after the sperm has penetrated the ovum.

5. **Conclusion:** The first step in the activation of the ovum during fertilization is the fertilizing and anti-fertilizing reaction. This reaction is crucial as it prepares the ovum for the sperm to penetrate.

6. **Final Answer:** The correct answer is **Option b: Fertilizing, anti-fertilizing reaction**.

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