Which of the following mutations would be most likely to have a harmful effect on an organism ? (a) a base-pair substitution (b) a single base deletion near the

Which of the following mutations would be most likely to have a harmful effect on an organism ? (A) a base-pair substitution (B) a single base deletion near the middle of an intron (C) a single base deletion close to the end of the coding sequence (D) a single base insertion near the start of the coding sequence