Which base is present in $RNA$ instead of $Thymine$?

In a nucleoside,a base is attached at the $1^{\prime}$ position of the sugar moiety. $A$ nucleotide is formed by linking a phosphoric acid unit to the sugar unit of a nucleoside. At which position of the sugar unit is the phosphoric acid linked in a nucleoside to give a nucleotide?

Which base is present in $RNA$ but not in $DNA$?

Which of the following bases is present in $DNA$?

In both $DNA$ and $RNA$,the heterocyclic base and phosphate ester linkages are at which positions of the sugar molecule?

In $DNA$ and $RNA$,the heterocyclic base and phosphate ester are attached to which carbons of the sugar molecule,respectively?