Biology · Biotechnology and PCR

The three major steps of a Polymerase Chain Reaction (PCR) cycle are Denaturation, Annealing, and Extension. Consider the following statements regarding PCR: (i) Denaturation is performed at high temperature (around 94–96 °C) to separate double-stranded DNA. (ii) Annealing involves binding of primers to single-stranded DNA at a lower temperature. (iii) Extension is carried out using a thermostable DNA polymerase (such as Taq polymerase) at around 72 °C. (iv) Primers are not required during the extension phase. Which of the statements given above are correct?