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Which nitrogenous base is present only in RNA and not in DNA?

easy MCQ 1 mark Class 12 · Biology · Molecular Basis of Inheritance
  1. Adenine (A)
  2. Guanine (G)
  3. Thymine (T)
  4. Uracil (U)
Answer
Uracil (U)

The correct answer is Uracil (U) — Select the base that is exclusive to RNA: uracil.

Step-by-step solution

  1. Identify the bases that are common to both DNA and RNA: adenine, guanine, cytosine.
  2. Recall that thymine is replaced by uracil in RNA.
  3. Select the base that is exclusive to RNA: uracil.
Common mistake: Choosing thymine instead of uracil

Concept tested: RNA‑specific base

Published · How this solution was prepared and checked

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