Final answer:
DNA replication is a highly accurate process, but mistakes can occasionally occur. Repair mechanisms correct the mistakes, but in rare cases, mistakes can lead to mutations.
Step-by-step explanation:
DNA replication is a highly accurate process, but mistakes can occasionally occur, such as a DNA polymerase inserting a wrong base. Uncorrected mistakes may sometimes lead to serious consequences, such as cancer. Repair mechanisms correct the mistakes. In rare cases, mistakes are not corrected, leading to mutations; in other cases, repair enzymes are themselves mutated or defective.