Which is not found in DNA ?

Options

A. Deoxy ribose sugar
B. 5-methyl uracil
C. Demethylated thymine
D. `H_(3)PO_(4)`

Answer

To solve the question "Which is not found in DNA?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Components of DNA**:
- DNA is composed of three main components: deoxyribose sugar, nitrogenous bases, and a phosphate group.

2. **List the Nitrogenous Bases**:
- The nitrogenous bases found in DNA are adenine (A), thymine (T), cytosine (C), and guanine (G).

3. **Examine the Options**:
- We need to analyze the provided options to see which one is not a component of DNA.

4. **Evaluate Each Option**:
- **Option 1: Deoxyribose Sugar** - This is a component of DNA.
- **Option 2: 5-Methyl Uracil (Thymine)** - Thymine is indeed a nitrogenous base found in DNA.
- **Option 3: Demethylated Thymine (Uracil)** - Uracil is not found in DNA; it is found in RNA instead.
- **Option 4: Phosphoric Acid** - This is part of the phosphate group in DNA.

5. **Conclusion**:
- The correct answer is **Option 3: Demethylated Thymine (Uracil)**, as it is not found in DNA.

### Final Answer:
**Demethylated Thymine (Uracil)** is not found in DNA.

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