Final answer:
Mutations can occur due to mistakes in DNA replication. If these mistakes are not corrected, they can lead to mutations.
Step-by-step explanation:
Mutations can occur due to mistakes in DNA replication. DNA replication is a highly accurate process, but mistakes can occasionally occur, such as a DNA polymerase inserting a wrong base. If these mistakes are not corrected, they can lead to mutations. Repair mechanisms are usually in place to correct these mistakes, but in some cases, mistakes are not repaired, leading to mutations.