Experiments show that the enzymes that actually copy our DNA may make mistakes (insert the wrong nucleotide) as frequently as 1 in every 1000 base pairs. However, by the time a cell has completed the process of DNA replication, less than 1 in 1 million nucleotides appears to have been miscopied. What accounts for this discrepancy?
a) Proofreading by DNA polymerase.
b) Mismatch repair mechanisms.
c) Excision repair mechanisms.
d) Telomerase activity.