In which stage the chromosomes appear thin and long thread-like

Options

A. leptotene
B. zygotene
C. prophase
D. pachytene

Answer

To answer the question "In which stage do the chromosomes appear thin and long thread-like?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Chromosome Structure**:
- Chromosomes are made up of chromatin, which is a complex of DNA and proteins. During cell division, they undergo condensation.

2. **Identifying the Stages of Meiosis**:
- The question refers to the stages of meiotic prophase 1. The stages include:
- Leptotene
- Zygotene
- Pachytene
- Diplotene
- Diakinesis

3. **Focusing on Leptotene**:
- Leptotene is the first stage of prophase 1 in meiosis. During this stage, the chromosomes begin to condense and become visible under a microscope.

4. **Characteristics of Leptotene**:
- In the leptotene stage, chromosomes appear as thin and long thread-like structures. This is due to the initial condensation of chromatin after DNA replication.

5. **Conclusion**:
- Based on the characteristics of the stages of meiotic prophase 1, the correct answer to the question is **Leptotene**.

### Final Answer:
The chromosomes appear thin and long thread-like during the **Leptotene** stage.

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