Human Reproduction — BIOLOGY STD 12 Science — Question

$I.$ Polymerase Chain Reaction $(PCR)$ is a technique of synthesizing multiple copies of the desired gene in vitro

$II.$ This technique was developed by Kary Mullis in $1985$

$III.$ A single $PCR$ amplification cycle involves three basic steps; denaturation, annealing and extension

Which of the statement given above are correct?

A drug used for ___$A$___ patients is obtained from a species of the organism ___$B$___ .

The one correct option for the two blanks is