Question

Which of the following is/are present both in DNA and RNA? figure [H]

figure

• A. I, II
• B. III only
• C. II only
• D. I, IV

Hint:

DNA has Thymine; RNA has Uracil. A, G, C are shared.

Answer 1

The Correct Option is B

Step 1: Recall the bases of DNA.
DNA is built from four nitrogen bases: Adenine, Guanine, Cytosine and Thymine.

Step 2: Recall the bases of RNA.
RNA also uses four bases: Adenine, Guanine, Cytosine and Uracil.

Step 3: Spot the difference.
The only difference is that DNA has Thymine while RNA replaces it with Uracil. So Thymine is unique to DNA and Uracil is unique to RNA.

Step 4: Find the common bases.
The bases present in both DNA and RNA are Adenine, Guanine and Cytosine.

Step 5: Match with the listed structures.
Among the structures shown, the option that picks the base common to both nucleic acids matches choice III.

Step 6: State the answer.
So the correct choice is III only.
\[ \boxed{\text{III only}} \]