Final answer:
The highest frequency of replication errors occurs when DNA polymerases copy short, repeated sequences called microsatellites.
Step-by-step explanation:
The highest frequency of replication errors occurs when DNA polymerases copy short, repeated sequences called microsatellites. These are short segments of DNA made up of repeating nucleotide sequences. During replication, if these microsatellites are not properly copied, errors can occur, leading to mutations.