Which of the following contributes to the double helical structure of $DNA$?

Which of the following bases is found only in $RNA$ but not in $DNA$?

If on a strand of $DNA$ the base sequence is $ATTGACGCAT$ then the sequence transcription on $RNA$ would be

Which of the following pyrimidine base is present in $RNA$?

Uracil is a base present in $RNA$ with the following structure. The percentage of $N$ in uracil is $............$.
Given:
Molar mass $N = 14 \, g \, mol^{-1} ; O = 16 \, g \, mol^{-1} ; C = 12 \, g \, mol^{-1} ; H = 1 \, g \, mol^{-1}$.

The pyrimidine bases present in $DNA$ are