The polymerase chain reaction $(PCR)$ technology was discovered by

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: When a particular restriction enzyme cuts a strand of $DNA$,overhanging stretches or sticky ends are formed.
Reason $(R)$: Some restriction enzymes cut the strand of $DNA$ a little away from the centre of the palindromic site.
In the light of the above statements,choose the correct answer from the options given below:

How are antibiotics used in genetic engineering?

Which of the following is not a palindromic $DNA$ sequence?

$pBR322$ was the first artificial cloning vector developed in $...A...$ by $...B...$ and $...C...$ from $E. coli$ plasmid. Here $A, B$ and $C$ can be:

Which one of the following is commonly used in the transfer of foreign $DNA$ into crop plants?