Balbiani rings (puffs ) are sites of

Options

A. DNA replication
B. RNA and protein synthesis
C. Synthesis of polysaccharides
D. Synthesis of lipids

Answer

To answer the question about Balbiani rings (puffs) and their function, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Balbiani Rings**:
- Balbiani rings, also known as puffs, are specific regions on polytene chromosomes that appear as swollen areas during certain developmental stages.

2. **Function of Balbiani Rings**:
- These rings are indicative of active gene transcription. The DNA in these regions uncoils and becomes accessible for transcription.

3. **Transcription Process**:
- Within the Balbiani rings, the uncoiled DNA is transcribed into messenger RNA (mRNA). This process is essential for the synthesis of proteins.

4. **Conclusion**:
- Since Balbiani rings are primarily involved in the synthesis of RNA (specifically mRNA) and subsequently in protein synthesis, we can conclude that they are sites of RNA and protein synthesis.

5. **Final Answer**:
- Therefore, the correct answer to the question is option B: RNA and protein synthesis.