4. What technique would a scientist use to produce many copies of a
desired piece of DNA?||

They can use a technique called Polymerase Chain Reaction. This can be done in a test tube or even in a organism. It usually relies on something called  Thermostable DNA Polymerase and Taq polymerase. It requires DNA primers that is designed specifically for that DNA region (interest).

six grader is what i am ssorry

no i don't feel that humans have oversubscribed some medications