The nitrogenous base not present in DNA is
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Uracil
DNA contains adenine, guanine, cytosine, and thymine.
These bases pair specifically in the DNA double helix: Adenine pairs with Thymine through two hydrogen bonds, and Guanine pairs with Cytosine through three hydrogen bonds.
Uracil is not present in DNA.Instead, uracil is found in RNA (Ribonucleic Acid) where it replaces thymine.
Thus, RNA contains: • Adenine • Uracil • Guanine • Cytosine
Therefore, the nitrogenous base that is not present in DNA is uracil.