Answer: DNA ligase.
Explanation:
Polymerase chain reaction is a technique used in molecular biology by scientists to make several copies of a DNA sample which enable them to take a smaller portions of it and expand it for more detailed study.
PCR mixture is premixed and contain thermostable DNA polymerase, oligonucleotides primer, four deoxynucleodide triphosphates, Magnesium chlorides, a propietary buffer.
