Thymine differs from uracil in having

Options

A. `CH_(3)` group
B. `C = O` group
C. CHO group
D. COOH group

Answer

To solve the question "Thymine differs from uracil in having," we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Molecules**: Understand that thymine and uracil are both nitrogenous bases found in nucleic acids. Thymine is found in DNA, while uracil is found in RNA.

2. **Chemical Structure Analysis**: Examine the chemical structures of both thymine and uracil.
- Thymine has a methyl group (-CH3) attached to its structure.
- Uracil does not have this methyl group.

3. **Locate the Difference**: The key difference lies in the presence of the methyl group. Specifically, thymine has a methyl group at the 5th carbon position, which is absent in uracil.

4. **Conclusion**: Based on the analysis, we conclude that thymine differs from uracil in having a methyl group at the 5th carbon.

5. **Final Answer**: Therefore, the answer to the question is that thymine differs from uracil in having a methyl group.