Genetic engineering is connected with

How is gene therapy useful for the treatment of various diseases?

Match the following columns.

Column-$I$	Column-$II$
$(A)$ Gene therapy	$(1)$ Effort to fix a functional gene
$(B)$ Humulin	$(2)$ $A$ single-stranded $DNA$ or $RNA$ tagged with a radioactive molecule
$(C)$ Probe	$(3)$ Diagnostic test
$(D)$ $ELISA$	$(4)$ Diabetes

The given figure represents pro-insulin. Identify the $A, B$ and $C$ peptides corresponding to $P, Q$ and $R$ respectively.

In which bacteria was the gene for insulin cloned?

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 $Bacillus \text{ } thuringiensis$.