When mitosis occurs, the dna inside the cell's nucleus must replicate. the new cell that is formed has an identical copy of its parent cell's dna. that means it has the same information coded in its genes. during dna replication, how is an accurate new copy of dna formed? a. dna helicases add nucleotides to the exposed bases and ensure the formation of hydrogen bonds. b. replication forks ensure that dna polymerases cannot attach to the old dna molecule. c. during dna replication uracil bases hold the place of all thymine bases until the newly formed double helix is able to form hydrogen bonds. d. dna polymerases add nucleotides to the exposed base pairs according to base-pairing rules.