In a majority of sexually reproducing organisms, the gametes are -

Options

A. Isogametes
B. Homogametes
C. Hemigametes
D. Heterogametes

Answer

**Step-by-Step Solution:**

1. **Understanding Gametes**: In sexually reproducing organisms, gametes are the reproductive cells that fuse during fertilization to form a zygote. They are crucial for sexual reproduction.

2. **Types of Gametes**: There are three main types of gametes based on their morphology:
- **Isogametes**: These are gametes that are morphologically identical. They look the same and have similar structures. An example would be certain algae.
- **Hogametes**: These are also identical in structure but may differ in some anatomical aspects. They are less commonly referenced in biological discussions.
- **Heterogametes**: These are the most common type of gametes in sexually reproducing organisms. They are morphologically different, typically with male gametes being smaller and motile, while female gametes are larger and often immotile.

3. **Prevalence of Heterogametes**: In the majority of sexually reproducing organisms, heterogametes are predominant. This means that most organisms produce two distinct types of gametes.

4. **Examples**: Humans are a classic example of organisms that produce heterogametes. The male gamete (sperm) is small and motile, while the female gamete (egg) is larger and typically immotile.

5. **Conclusion**: Therefore, the correct answer to the question is that in a majority of sexually reproducing organisms, the gametes are heterogametes.

**Final Answer**: In a majority of sexually reproducing organisms, the gametes are heterogametes.

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