Answer:
D. Scientists use viruses to insert specific gene sequences.
Step-by-step explanation:
Gene Therapy:
- Gene therapy is a treatment approach for genetic diseases that involves either the removal or the replacement of the defective gene with a normal one.
- Gene therapy is currently an experimental procedure that utilizes in-vivo (directly into body) and ex-vivo (taking cells outside, treating them and injecting them back into the body.
- Gene therapy involves the use of two kinds of vectors i.e. vehicles for carrying and injecting the normal gene into body cells:
- Viral vectors are modified viruses that infect the target cells and inject the normal gene in to them.
- Non-viral vectors mostly comprise polymers (such as lipid based particles etc.) that encapsulate the normal gene and fuse with the cell membrane of the target cells.