Which enzyme is used in the $ELISA$ test?

In what form is human insulin synthesized,and what does it contain?

Identify the function of the enzyme Adenosine Deaminase $(ADA)$.

Find the correct statements from the following:
$I.$ Gene therapy is a genetic engineering technique used to treat diseases at the molecular level.
$II.$ Calcitonin is a medically useful recombinant product in the treatment of infertility.
$III.$ Bt toxin is a biodegradable insecticide obtained from $Bacillus \text{ } thuringiensis$.

Consider the following statements about therapeutic drugs:
$I$. The recombinant $DNA$ technology is used for the production of therapeutic drugs which are safe and effective.
$II$. It avoids unwanted immunological responses,commonly observed with similar products isolated from non-human sources.
$III$. About $30$ recombinant therapeutics have been approved for human use in the world,including India.
Which of the statements given above are correct?

Which of the following companies started selling humulin in $1983$?