Adenosine deaminase $(ADA)$ deficiency is most commonly caused by which genetic abnormality?

Which new strain of bacteria was produced through biotechnology?

Given below are two statements:
Statement $I$: $Adenosine \ deaminase$ is crucial for the immune system to function.
Statement $II$: $Adenosine \ deaminase$ deficiency can be cured only by bone marrow transplantation.
In the light of the above statements, choose the correct answer from the options given below.

Identify the incorrect statement.

Which one of the following is the first genetically engineered medicine?

Statement-$I$: In vitro fertilisation leading to a test tube baby is a part of biotechnology.
Statement-$II$: Developing a $\text{DNA}$ vaccine is a part of biotechnology.