Formation of activation calyx in the egg takes place

Options

A. Before fertilization
B. After fertilization
C. At the time of cleavage
D. At the time of amphimixis.

Answer

**Step-by-Step Solution:**

1. **Understanding the Activation Calyx**: The activation calyx is a structure that forms around the egg after it has been fertilized. It plays a crucial role in the fertilization process and subsequent development of the embryo.

2. **Identifying the Process**: The formation of the activation calyx is closely linked to the interaction between the sperm and the egg. When a sperm successfully penetrates the egg, it triggers a series of biochemical changes.

3. **Timing of Formation**: The activation calyx forms as a response to the activation of the egg by the sperm. This means that the formation occurs after the sperm has fertilized the egg.

4. **Evaluating the Options**:
- Option A (before fertilization) is incorrect because the activation calyx is formed as a result of fertilization.
- Option B (after fertilization) is correct as the activation calyx forms following the interaction of sperm and egg.
- Option C (at the time of cleavage) is incorrect since cleavage refers to the division of the fertilized egg, which occurs after the formation of the activation calyx.
- Option D (at the time of amphimixis) is also incorrect as amphimixis refers to the fusion of the sperm and egg nuclei, which occurs during fertilization, but the activation calyx forms after this event.

5. **Conclusion**: Based on the understanding of the activation calyx and the timing of its formation, the correct answer is option B: after fertilization.

**Final Answer**: Option B: After fertilization.

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