The type of bond connecting two nucleotides is

The total number of hydrogen bonds in a $DNA$ double helix strand,where one strand has the following sequence of bases,is $...........$
$5^{\prime}-G-G-C-A-A-A-T-C-G-G-C-T-A-3^{\prime}$

The average energy of each hydrogen bond in $A-T$ pair is $x \, kcal \, mol^{-1}$ and that in $G-C$ pair is $y \, kcal \, mol^{-1}$. Assuming that no other interaction exists between the nucleotides,the approximate energy required in $kcal \, mol^{-1}$ to split the following double stranded $DNA$ into two single strands is:
$A$-$T$-$A$-$T$-$G$-$C$-$A$-$G$
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$T$-$A$-$T$-$A$-$C$-$G$-$T$-$C$

The difference between $DNA$ and $RNA$ is based on the presence or absence of a hydroxyl group at which carbon atom of the sugar molecule?

Which of the following is not a pyrimidine?

Which pyrimidine bases are present in $DNA$?