Which of the following is used for gene transfer in animals?

In the treatment of $ADA$ deficiency during gene therapy,which cells are collected from the patient's blood?

Hybridomas are the result of fusion of

The use of living organisms for human welfare is called......

Which of the following peptide chain is removed during the maturation of proinsulin into insulin?

Which of the following is/are correct about Adenosine Deaminase $(ADA)$ deficiency?
$I$. In the absence of adenosine deaminase enzyme,purine metabolism is disturbed and $T$-lymphocytes fail to function.
$II$. $ADA$ deficiency is caused by the deletion of the gene for $ADA$.
$III$. In some cases,it can be cured by bone marrow transplantation and enzyme replacement therapy. But in both approaches,the patients are not completely cured.
$IV$. For permanent cure,genes isolated from the bone marrow cells producing $ADA$ at early embryonic stages can be a possible cure.
Which of the above statements are correct?