The first clinical gene therapy was given in $1990$ to a $4$-year-old girl to treat deficiency of:

The Adenosine deaminase deficiency results into:

Which of the following statements is not correct?

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 $Bacillus \text{ } thuringiensis$.

What is the primary objective of genetic engineering?

Which of the following methods,other than gene therapy,has been used for the treatment of $ADA$ deficiency?