In Lederberg's replica plating experiment,what should be used to obtain streptomycin-resistant strains?

By using the diagram,select the correct option for $X$ and $Y$.

The $1$ gene $1$ enzyme relationship was first established in .......... .

$A$ : $5S$ $rRNA$ and surrounding protein complex provides binding site of $tRNA$.
$R$ : $tRNA$ is soluble $RNA$ with unusual bases.

Which of the following is not a correct statement regarding $\text{RNA}$?

Consider the following four statements $(a-d)$ and select the option which includes all the correct ones only $:-$
$(a)$ Transcription and translation can be coupled in bacteria.
$(b)$ The split gene arrangements represent the advanced feature of the genome.
$(c)$ The process of splicing represents the dominance of $\text{RNA-}$world.
$(d)$ The presence of introns in split gene is reminiscent of antiquity.