Majority of sexually reproducing organisms form

Options

A. Isogametes
B. Homogametes
C. Heterogametes
D. More than one option is correct

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Terms:**
- The question asks about the majority of sexually reproducing organisms and the types of gametes they form. We need to define the terms isogametes, homogametes, and heterogametes.

2. **Isogametes:**
- Isogametes are gametes that are similar in size and shape. The prefix "iso" means "same." Therefore, isogametes do not differ from each other.

3. **Homogametes:**
- Homogametes are essentially the same as isogametes. They also refer to gametes that are similar in size and shape. The prefix "homo" means "same," indicating that these gametes are indistinguishable from one another.

4. **Heterogametes:**
- Heterogametes refer to gametes that are different in size and shape. The prefix "hetero" means "different." In sexually reproducing organisms, male and female gametes are typically heterogametes, as they differ in size and shape (e.g., sperm and ovum).

5. **Examples in Humans:**
- In humans, sperm (male gamete) and ovum (female gamete) are examples of heterogametes. The sperm is small and motile, while the ovum is larger and non-motile. This difference in size and shape confirms that they are heterogametes.

6. **Conclusion:**
- Therefore, the majority of sexually reproducing organisms form heterogametes, as they produce male and female gametes that are different in size and shape.

**Final Answer:**
The correct answer is **heterogametes**.

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