The base present in DNA, but not in RNA is

Options

A. guanine
B. adenine
C. uracil
D. thymine

Explanation

To solve the question "The base present in DNA, but not in RNA is," we can follow these steps:

### Step 1: Understand the Components of DNA and RNA
Both DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are nucleic acids made up of three components: a phosphate group, a sugar, and nitrogenous bases.

### Step 2: Identify the Sugars
- The sugar in DNA is **deoxyribose**.
- The sugar in RNA is **ribose**.

### Step 3: List the Nitrogenous Bases
There are two types of nitrogenous bases:
1. **Purines**: Adenine (A) and Guanine (G)
2. **Pyrimidines**: Cytosine (C), Thymine (T), and Uracil (U)

### Step 4: Compare the Bases in DNA and RNA
- **DNA Bases**: Adenine (A), Guanine (G), Cytosine (C), and Thymine (T)
- **RNA Bases**: Adenine (A), Guanine (G), Cytosine (C), and Uracil (U)

### Step 5: Identify the Unique Base
Now, we need to identify which base is present in DNA but not in RNA:
- Both DNA and RNA contain Adenine (A), Guanine (G), and Cytosine (C).
- **Thymine (T)** is present in DNA but **not** in RNA.
- **Uracil (U)** is present in RNA but **not** in DNA.

### Conclusion
The base that is present in DNA but not in RNA is **Thymine (T)**.

### Final Answer
**Thymine (T)** is the base present in DNA but not in RNA.

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