Which enzyme is used in the $ELISA$ test?

First biochemical to be produced commercially by microbial cloning and genetic engineering is:

Which of the following are used in $MRI$ to detect physiological changes in living tissues?
$(i)$ $UV$ rays $(ii)$ Strong magnetic fields $(iii)$ $\gamma$-rays $(iv)$ $X$-rays

$A$: Recombinant $DNA$ technology is less effective in therapeutic drug production.
$R$: Recombinant therapeutics induce unwanted immunological responses.

Human insulin is being commercially produced from a transgenic species of

$ADA$ deficiency results in