In eukaryotes, RNA polymerase II transcribes

Options

A. the precursor of tRNA
B. the precursor of mRNA
C. the precursor of snRNA
D. the precursor of rRNA

Answer

To solve the question regarding what RNA polymerase II transcribes in eukaryotes, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding RNA Polymerases**:
- In eukaryotes, there are three main types of RNA polymerases: RNA polymerase I, RNA polymerase II, and RNA polymerase III.

2. **Identifying Functions of Each RNA Polymerase**:
- **RNA Polymerase I**: Responsible for synthesizing precursor ribosomal RNA (rRNA).
- **RNA Polymerase II**: Responsible for synthesizing precursor messenger RNA (mRNA).
- **RNA Polymerase III**: Responsible for synthesizing precursor transfer RNA (tRNA) and small nuclear RNA (snRNA).

3. **Analyzing the Options**:
- **Option 1**: Precursor of tRNA - This is transcribed by RNA polymerase III, not II.
- **Option 2**: Precursor of mRNA - This is transcribed by RNA polymerase II.
- **Option 3**: Precursor of snRNA - This is also transcribed by RNA polymerase III.
- **Option 4**: Precursor of rRNA - This is transcribed by RNA polymerase I.

4. **Conclusion**:
- Based on the functions of the RNA polymerases, the correct answer is that RNA polymerase II transcribes the precursor of mRNA.

### Final Answer:
**RNA polymerase II transcribes the precursor of mRNA.**

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