Lateral conjugation of Spirogyra occurs in individuals
1 Free floating
2 Homothallic
3 Heterothallic
4 Having different characters.

Options

A. Free floating
B. Homathallic
C. Heterothallic
D. Having different characters.

Answer

To solve the question regarding the lateral conjugation of Spirogyra, we need to analyze the options provided and understand the reproductive mechanisms of Spirogyra.

### Step-by-Step Solution:

1. **Understanding Spirogyra**:
- Spirogyra is a filamentous green algae characterized by its unbranched and filamentous thallus. It reproduces both asexually and sexually.

2. **Sexual Reproduction in Spirogyra**:
- Sexual reproduction occurs through a process called conjugation. During this process, the protoplasmic contents of vegetative cells act as gametes.

3. **Types of Conjugation**:
- There are two types of conjugation in Spirogyra: lateral conjugation and scleriform conjugation.
- Lateral conjugation is rare and occurs in homothallic species (monoecious), while scleriform conjugation occurs in heterothallic species (dioecious).

4. **Lateral Conjugation Process**:
- In lateral conjugation, fusion occurs between gametes from two adjacent cells of the same filament. The septum between these cells develops outgrowths that form male and female gametangia, leading to the formation of a conjugation tube.

5. **Analyzing the Options**:
- **Option 1: Free floating** - This does not specifically relate to the type of conjugation.
- **Option 2: Homothallic** - This is correct as lateral conjugation occurs in homothallic species.
- **Option 3: Heterothallic** - This is incorrect as lateral conjugation does not occur in heterothallic species.
- **Option 4: Having different characters** - This is also incorrect as it does not pertain to lateral conjugation.

6. **Conclusion**:
- Based on the analysis, the correct answer is **Option 2: Homothallic**.

### Final Answer:
The lateral conjugation of Spirogyra occurs in individuals that are **Homothallic**.

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