Final answer:
Unrepaired DNA with single nucleotide changes can contribute to uncontrolled cell division, leading to the development of cancer.
Step-by-step explanation:
Unrepaired DNA with single nucleotide changes can contribute to uncontrolled cell division, leading to the development of cancer. When errors occur in the replication of DNA during the S phase of the cell cycle, mutations can be passed on to daughter cells.
If these mutations occur within genes, gene mutations can result. Gene mutations can give rise to faulty proteins that are involved in cell reproduction, leading to uncontrolled growth of mutated cells and the formation of a tumor.