DNA replication is the process by which a cell makes an identical copy of its DNA. It involves unwinding the DNA double helix and using DNA polymerases to synthesize new strands that are complementary to the original strands. This results in two identical DNA molecules, each with one original strand and one new strand. The key stages are initiation of replication at the origin of replication, unwinding of the DNA strands by helicase, synthesis of new strands in the 5' to 3' direction by DNA polymerases, and ligation to finish the replication. DNA replication is semiconservative, meaning each new DNA molecule contains one original and one new strand.