Define “gene therapy.”

Gene therapy refers to a method that involves inserting new genes into an individual's genome to treat or prevent diseases. This approach aims to correct or compensate for defective genes that are responsible for disease development. By adding functional copies of genes, gene therapy can potentially address the underlying genetic issues associated with various disorders, including genetic conditions, some types of cancer, and certain viral infections.

The other options involve techniques related to genetics and biochemistry but do not accurately define gene therapy. For instance, replacing damaged proteins in cells pertains more to protein replacement therapies rather than gene insertion itself. Editing genes to enhance traits, while relevant to genetic engineering and technologies like CRISPR, does not align strictly with the definition of gene therapy, which focuses on treating diseases. Cloning entire organisms is a separate biological process dealing with reproduction rather than the correction or alteration of specific genes to treat diseases. Therefore, the essence of gene therapy is best captured by the method of inserting new genes into the genome for therapeutic purposes.