Which base is not present in the $DNA$ structure?

Which of the following is/are correct?

. . . . . . nucleotide is not present in $RNA$.

Which carbon atom of ribose sugar is joined to the nitrogen base to form a nucleoside?

Which from the following nitrogen bases of nucleic acids is derived from purine?

$DNA$ fingerprinting is a technique used to identify individuals by their genetic makeup. It relies on the fact that the sequence of nucleotides in $DNA$ is unique to every individual,except for identical twins. The process involves isolating $DNA$,fragmenting it using restriction enzymes,separating the fragments via gel electrophoresis,and then using probes to visualize specific patterns ($DNA$ profiles). Uses: $1$. Forensic investigations for solving crimes. $2$. Determining paternity or maternity. $3$. Identifying genetic disorders and hereditary diseases.