Which of the following is/are the bases of DNA ?
(A) Adenine
(B) Uracil
(C) Thymine
(D) Cytosine
Choose the correct answer from the options given below :
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A), (C) and (D) only
Nucleic acids contain heterocyclic nitrogenous bases of two kinds: purines (adenine, guanine) and pyrimidines (cytosine, thymine, uracil).
(A) Adenine — Correct. Present in DNA (and RNA).
(B) Uracil — Incorrect. Found only in RNA; DNA has thymine in its place.
(C) Thymine — Correct. Present only in DNA.
(D) Cytosine — Correct. Present in DNA (and RNA).
NCERT (2026-27 edition):
Chemical Composition of Nucleic Acids – …
