Gene therapy, which includes the correction of defective genes, is a significant part of the human genome project. which of these is an application of the technique?
a: a new protein, which can repair defective genes, is injected.
b: mutated dna sequences, which can pair with existing genes, are introduced.
c: the dna sequences of the entire genomes of disease-causing microbes are compared.
d: a new gene, which codes for the protein that can repair defective genes, is introduced.