Which of the following is not used in the Southern hybridization technique for chromosomal $DNA$ analysis?

Illustrate the design of a bioreactor. Highlight the difference between a flask in your laboratory and a bioreactor which allows cells to grow in a continuous culture system.

What type of method is the $PCR$ technique?

The blue and white selectable markers have been developed which differentiate recombinant colonies from non-recombinant colonies on the basis of their ability to produce colour in the presence of a chromogenic substrate.
Given below are two statements about this method :
Statement-$I$ : The blue coloured colonies have $\text{DNA}$ insert in the plasmid and they are identified as recombinant colonies.
Statement-$II$ : The colonies without blue colour have $\text{DNA}$ insert in the plasmid and are identified as recombinant colonies.
In the light of the above statements,choose the most appropriate answer from the options given below:

$DNA$ can be introduced into any cell by:

How many steps are there in one $PCR$ cycle?