Answer/Explanation:
The replication of DNA is semi-conservative, as each new molecule of DNA inherits one of the parental strands each, and one new strand each. DNA is replicated using the enzyme DNA polymerase, which synthesises a new strand by adding nucleotides in a sequence through complementary base pairing with the template strand. This occurs before the mitosis stage of the cell cycle, where the cell divides. Before this cell division happens, the cell has to pass certain checkpoints controlled by enzymes which ensure environmental conditions are optimal for dividing, and that the new DNA is free from errors.