The most vital and critical event of the sexual reproduction is

Options

A. gamete formation
B. gamete transport
C. gametic fusion
D. embryogenesis

Answer

**Step-by-Step Solution:**

1. **Understanding Sexual Reproduction**: Sexual reproduction involves the combination of genetic material from two parents to produce offspring. This process includes several key events.

2. **Identifying the Options**: The question provides four options:
- Gamete formation
- Gamete transport
- Gametic fusion
- Embryogenesis

3. **Evaluating Gamete Formation**:
- Gamete formation, or gametogenesis, is the process of producing specialized reproductive cells (gametes) such as sperm and eggs.
- While essential, this step alone does not ensure reproduction because the gametes must meet and combine.

4. **Evaluating Gamete Transport**:
- Gamete transport refers to the movement of gametes towards each other.
- In many species, sperm must swim to reach the egg. However, even if transport occurs, it does not guarantee that fertilization will happen.

5. **Evaluating Gametic Fusion**:
- Gametic fusion, also known as fertilization, is the process where the sperm and egg combine to form a zygote.
- This step is critical because it leads to the formation of a new organism. Without this fusion, no new life can begin.

6. **Evaluating Embryogenesis**:
- Embryogenesis is the development of the embryo from the zygote.
- This process cannot occur without gametic fusion, as it is dependent on the fertilization event.

7. **Conclusion**:
- Among the options, gametic fusion (fertilization) is the most vital and critical event in sexual reproduction because it directly leads to the formation of a new organism. Without fertilization, the subsequent processes of embryogenesis cannot occur.

**Final Answer**: The most vital and critical event of sexual reproduction is **gametic fusion**.

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