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

$DNA$ consists of two polynucleotide chains. Each chain forms a right-handed spiral with how many bases in one turn of the spiral?

Given below are two statements:
Statement $I$: $A$ unit formed by the attachment of a base to $1'-$position of sugar is known as nucleoside.
Statement $II$: When nucleoside is linked to phosphorous acid at $5'-$position of sugar moiety,we get nucleotide.
In the light of the above statements,choose the correct answer from the options given below:

In the double-strand helix structure of $DNA,$ thymine forms hydrogen bonds with

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

When $RNA$ is hydrolysed,there is no relationship among the quantities of different bases obtained. What does this fact suggest about the structure of $RNA$?