Identify '$Z$' and '$Q$' in the given figure of $pBR322$.

Assertion : $Agrobacterium$ $tumefaciens$ is popular in genetic engineering because this bacterium is associated with the roots of all cereal and pulse crops.
Reason : $A$ gene incorporated in the bacterial chromosomal genome gets automatically transferred to the crop with which the bacterium is associated.

An antibiotic resistance gene in a vector helps in the selection of:

$Escherichia$ $coli$ $(E. coli)$ is widely used in biological research because:

$A$: $cDNA$ libraries are important to scientists in human genomics.
$R$: $cDNA$ is a synthetic type of $DNA$ generated from $mRNA$.

Which of the following restriction enzymes used in recombinant $DNA$ technology produces staggered cuts (sticky ends) in $DNA$?