Production of a human protein in bacteria by genetic engineering is possible because

What is downstream processing?

From the following tools/techniques of genetic engineering,identify those which are required for cloning a bacterial gene in animal cells and choose the correct option:
$I$. Endonuclease $II$. Ligase
$III$. $A. tumefaciens$ $IV$. Microinjection
$V$. Gene gun $VI$. Lysozyme
$VII$. Cellulase $VIII$. Electrophoresis

The Polymerase Chain Reaction $(PCR)$ technique is used for ........

At which stage of $PCR$,does the template join with the primer?

It is used to detect $HIV$ in suspected $AIDS$ patient and detect mutations in genes in suspected cancer patient too.