Which one is not transcribed by DNA ?

Options

A. Exons
B. Introns
C. DNA
D. tRNA

Explanation

To answer the question "Which one is not transcribed by DNA?", we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding Transcription**:
- Transcription is the process by which DNA is used to synthesize RNA. During this process, the information encoded in DNA is converted into messenger RNA (mRNA).

2. **Identifying Types of RNA**:
- There are several types of RNA that can be transcribed from DNA, including:
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Ribosomal RNA (rRNA)
- Introns (non-coding regions that are transcribed but later removed)

3. **Defining What is Not Transcribed**:
- The question asks for something that is not transcribed by DNA. In the context of molecular biology, DNA itself is not transcribed. Instead, it serves as a template for the synthesis of RNA.

4. **Clarifying the Options**:
- If we consider the options given in the context of the question, we can conclude that while mRNA, tRNA, and rRNA are all transcribed from DNA, DNA itself is not transcribed.

5. **Conclusion**:
- Therefore, the correct answer to the question "Which one is not transcribed by DNA?" is **DNA itself**.