Which of the following is used for the treatment of genetic disorders?

What is the full form of $ADA$?

Statement-$I$: At present, $30$ recombinant therapeutics have been approved for human use the world over.
Statement-$II$: Recombinant therapeutics do not induce unwanted immunological responses, as is common in the case of similar products isolated from non-human sources.
Choose the correct answer from the options given below:

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

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

How was insulin obtained before the advent of $rDNA$ technology? What were the problems encountered?