Amphimixis is

Options

A. (a) reaction of antifertilizin and fertilizin
B. (b) fusion of male and female pronuclei
C. (c) formation of reception cone by ovum
D. (d) penetration of sperm into ovum

Answer

### Step-by-Step Solution:

1. **Definition of Amphimixis**:
- Amphimixis is a term synonymous with sexual reproduction. It refers to the process where two different gametes (egg and sperm) fuse together.

2. **Understanding Fertilization**:
- The fusion of the male and female gametes during sexual reproduction is known as fertilization. This is the key process that defines amphimixis.

3. **Analyzing the Options**:
- **Option A**: Reaction of antifertilizing and fertilizer - This is incorrect as there is no established term for this reaction.
- **Option B**: Fusion of male and female pro-nuclei - This is correct because it describes the actual fusion of the gametes' nuclei, which is a part of the fertilization process.
- **Option C**: Formation of reception cone by ova - This is incorrect as it describes a process that occurs when sperm approaches the ovum, but does not define amphimixis.
- **Option D**: Penetration of sperm into ovum - This describes a step in fertilization but does not encompass the entire definition of amphimixis.

4. **Conclusion**:
- From the analysis of the options, the most suitable answer is **Option B**: Fusion of male and female pro-nuclei, which accurately represents the concept of amphimixis.