19. When a region of DNA must be repaired by removing and replacing some of the nucleotides,what ensures that the new nucleotides are in the correct sequence?
(A)DNA cannot be repairedand this explains why mutations occur.
(B)Specific enzymes bind the correct nucleotides.
(C)Thenew nucleotides basepair accurately with those on the complementary strand.
(D)The repairenzyme recognizes the removed nucleotide and brings in an identical one to replace it.
(E)Thethree-dimensional structure determines the order of nucleotides.