$A$ : Recombinant $DNA$ technologies process has been less effective in therapeutic drug production.

$R$ : Recombinant therapeutics induce unwanted immunological responses.

Consider the following statements about insulin

$I$. Human insulin is made-up of $51$ amino acids arranged in two polypeptide chains

$II$. The two polypeptide chains are interconnected by two disulphide bridges

$III$. In mammals including humans, insulin is synthesized as a pro-hormone, which contains an extra stretch called the Cpeptide

$IV$. $C-$peptide is not present in the mature insulin

Which of the statements given above are correct?

Cry $II$ Ab and cry $I$ Ab produce toxins that control

Streptomycin is produced by or from which micro-organism streptomycin is prepared

Humulin is