The double-helical structure of $DNA$ is due to ....

The base present in $DNA$,but not in $RNA$ is

Among the following compounds,which one is found in $RNA$?

If one strand of a $DNA$ has the sequence $ATGCTTCA$,the sequence of the bases in the complementary strand is:

Identify the carbon atom numbered from $C_1^{\prime}$ to $C_5^{\prime}$ of the monosaccharide unit of a $DNA$ nucleotide that lacks an oxygen atom from the $-OH$ group.

Which one is not a constituent of nucleic acid?