Which of the following diagnostic tools allows the detection of very low concentration of bacteria or viruses by amplifying their nucleic acid?

Which method is used to amplify a desired gene in large numbers?

Explain how recombinant $DNA$ is introduced into a host cell or a living organism.

Explain how the synthesis of a gene of interest is performed using $PCR$.

Arrange the steps of $\text{rDNA}$ technology in the correct order$:-$
$(I.)$ Extraction of the desired gene product.
$(II.)$ Amplification of the gene of interest.
$(III.)$ Isolation of the desired $\text{DNA}$ fragment.
$(IV.)$ Ligation of the $\text{DNA}$ fragment into a vector.
$(V.)$ Insertion of $\text{rDNA}$ into the host.
The correct order is$:-$

Identify the diagram given below.