Which $RNA$ is formed after the maturation of $hnRNA$?

In which of the following places is messenger $RNA$ $(mRNA)$ formed in a living cell?

$RNA$ polymerase binds to the .........

In $DNA$,the promoter is the initiation site for .......

The enzyme involved in transcription is . . . . . . .

Which of the following statements are correct with reference to a transcription unit?
$A$. $A$ transcription unit in $DNA$ is defined primarily by three regions: promoter, structural gene and terminator.
$B$. The promoter is said to be located towards the $5'$-end of the structural gene.
$C$. The promoter is a $DNA$ sequence that provides binding site for $RNA$ polymerase.
$D$. The promoter defines the template and coding strands.
$E$. The terminator is located towards the $3'$-end of the coding strand and it defines the end of the process of transcription.
Choose the correct answer from the options given below: