Which of the following nitrogen bases is NOT found in DNA?

Uracil is the nitrogen base that is not found in DNA. DNA contains four nitrogenous bases: adenine, thymine, cytosine, and guanine. In contrast, uracil is a base that is present in RNA instead of thymine. While adenine pairs with thymine in DNA, in RNA, adenine pairs with uracil. This distinction between DNA and RNA is crucial for understanding their structural differences and functions in biological systems. The presence of uracil in RNA allows for unique processes such as transcription and translation, which are fundamental to protein synthesis. Hence, identifying uracil as the nitrogenous base absent in DNA reflects a key aspect of molecular biology regarding the roles and compositions of nucleic acids.