Which statements describe gene therapy? Check all that apply.
A. It cures all cases of cystic fibrosis.
B. It involves the modification of DNA. C. It is easy to apply to all cells affected by the disorder.
D. It attempts to replace a mutated gene with normal DNA. It does not always cure patients who use it.​

Even though the ostrich is a flightless bird, ostriches still possess wings that stretch approximately two meters across when fully extended. scientists speculate that when dinosaurs became extinct, some of the birds that lived during that time became land dwellers since they were able to consume the food that the dinosaurs once ate. over time, these species grew larger and heavier. eventually, the ostrich species became too big to fly. the wings found on ostriches are known as a. analogous structures. b. homologous structures. c. vestigial structures. d. symmetrical structures.