While scientists have made enormous discoveries, there is always more to learn. Knowledge is built on and reviewed. Sometimes new information reveals an error in understanding from the past. The study of how the world works is always ongoing.
While both will equate changes in a genetic chain, deletion would have more severe consequences. A substitution mutation usually only causes minor disorders and diseases, like sickle cell anemia. Whereas deletion causes much more serious diseases, like cystic fibrosis, and turner syndrome which is where a female is born with only one X chromosome.
It would be A. True. I hope this helped you. Have a good afternoon
