What type of method is the $PCR$ technique?

Polymerase chain reaction $\text{(PCR)}$ amplifies $\text{DNA}$ following the equation:

The components of a bioreactor are:
$I.$ An agitator system
$II.$ An oxygen delivery system
$III.$ Foam control system
$IV.$ Temperature control system
$V.$ $pH$ control system
$VI.$ Sampling ports to withdraw cultures periodically
Choose the correct option.

$A$ probe is used in which stage of genetic engineering?

Which of the following method$(s)$ is used to introduce foreign $DNA$ into host cells?

Stirred-tank bioreactors have been designed for