Fertilization is __________ in humans. (external/internal)

Answer

**Step-by-Step Solution:**

1. **Understanding Fertilization**: Fertilization is the process where male and female gametes (sperm and ovum) fuse together. This fusion is essential for the formation of a zygote, which eventually develops into an embryo.

2. **Types of Fertilization**: There are two main types of fertilization: external and internal.
- **External Fertilization**: This occurs outside the body. For example, in frogs, the male releases sperm into the water where the female releases her eggs, and fertilization occurs in the external environment.
- **Internal Fertilization**: This occurs inside the body. In humans, the male gametes (sperm) are deposited into the female reproductive tract during coitus, where they travel to meet the female gamete (ovum) for fertilization.

3. **Fertilization in Humans**: In humans, fertilization is classified as internal because the fusion of sperm and ovum takes place within the female reproductive system, specifically at the ampulla-isthmus junction of the fallopian tube.

4. **Conclusion**: Based on the definitions and examples provided, we can conclude that fertilization is internal in humans.

**Final Answer**: Fertilization is **internal** in humans.

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