To build up food reserves in the cytoplasm, chromosomes become unfolded to start transcription of mRNA and rRNA, during which phase of meiosis I ?

Options

A. Diakinesis
B. Zygotene
C. Diplotene
D. Leptotene

Explanation

To determine during which phase of meiosis I the chromosomes become unfolded to start the transcription of mRNA and rRNA for building up food reserves in the cytoplasm, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context of Meiosis**: Meiosis is a type of cell division that reduces the chromosome number by half and consists of two main stages: meiosis I and meiosis II. Meiosis I is further divided into five phases.

2. **Identify the Phases of Meiosis I**: The five stages of meiosis I are:
- Leptotene
- Zygotene
- Pachytene
- Diplotene
- Diakinesis

3. **Focus on the Requirement of the Question**: The question specifically asks about the phase where chromosomes unfold to start the transcription of mRNA and rRNA, which is necessary for building food reserves in the cytoplasm.

4. **Analyze Each Phase**:
- **Leptotene**: Chromosomes begin to condense but are not yet fully visible.
- **Zygotene**: Homologous chromosomes begin to pair up.
- **Pachytene**: Chromosomes are fully paired, and crossing over occurs.
- **Diplotene**: Chromosomes begin to separate but remain attached at chiasmata. This is also where the chromosomes unfold to allow transcription.
- **Diakinesis**: Chromosomes condense further and prepare for metaphase.

5. **Conclusion**: The phase where chromosomal unfolding occurs, allowing for the transcription of mRNA and rRNA, is the **Diplotene** stage of meiosis I.

### Final Answer:
**Diplotene**

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