Puffs or balbiani rings in salivary gland chromsosomes are sites of

Options

A. DNA replication
B. DNA duplication
C. RNA synthesis
D. Protein synthesis

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the function of puffs or Balbiani rings found in salivary gland chromosomes.

2. **Identifying the Structure**: Puffs, also known as Balbiani rings, are large, swollen areas on the chromosomes of certain organisms, particularly in the salivary glands of insects like Drosophila.

3. **Function of Puffs**: These structures are associated with regions of active gene expression. They are sites where transcription occurs, leading to the production of RNA.

4. **Analyzing the Options**:
- **Option A: DNA replication** - This refers to the process of copying DNA, which does not specifically involve puffs.
- **Option B: DNA duplication** - Similar to DNA replication, this is not the primary function of puffs.
- **Option C: RNA synthesis** - This is the process of creating RNA from a DNA template, which is indeed what occurs at the puffs.
- **Option D: Protein synthesis** - While RNA is involved in protein synthesis, the puffs themselves are not directly sites of protein synthesis.

5. **Conclusion**: Based on the analysis, the correct answer is **Option C: RNA synthesis**. Puffs or Balbiani rings are specifically sites of high RNA production.