Among the pyrimidines, this is common for both DNA and RNA

Options

A. Uracil
B. Cytosine
C. Thymine
D. Both 1 and 3

Answer

To solve the question "Among the pyrimidines, this is common for both DNA and RNA," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of DNA and RNA**:
- DNA (Deoxyribonucleic Acid) is double-stranded and contains the sugar deoxyribose.
- RNA (Ribonucleic Acid) is single-stranded and contains the sugar ribose.

2. **Identify the Types of Nitrogenous Bases**:
- Nitrogenous bases are categorized into two groups: purines and pyrimidines.
- **Purines**: Adenine (A) and Guanine (G) are common to both DNA and RNA.
- **Pyrimidines**: The pyrimidines include Cytosine (C), Thymine (T), and Uracil (U).

3. **List the Pyrimidines in DNA and RNA**:
- In DNA, the pyrimidines are Cytosine (C) and Thymine (T).
- In RNA, the pyrimidines are Cytosine (C) and Uracil (U).

4. **Determine the Common Pyrimidine**:
- From the lists, we see that Cytosine (C) is present in both DNA and RNA.
- Thymine (T) is only found in DNA, and Uracil (U) is only found in RNA.

5. **Select the Correct Answer**:
- Based on the analysis, the common pyrimidine between DNA and RNA is Cytosine (C).

### Final Answer:
Cytosine is the pyrimidine that is common for both DNA and RNA.

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