Final answer:
The correct answer is c. Replication, as it is not a discrete step in the PCR process, which consists of three steps: denaturation, annealing, and extension.
Step-by-step explanation:
The question asks which of the following is not a step done during the polymerase chain reaction (PCR) in DNA isolation and amplification labs. The correct answer is c. Replication. PCR consists of three primary steps: denaturation, annealing, and extension. Denaturation involves heating DNA to separate the two strands. Annealing cools the DNA strands allowing primers to attach to them. Extension is the addition of new nucleotides to the DNA strand by DNA polymerase. 'Replication' is a broader term that describes the entire process of copying DNA, but it is not a discrete step within the PCR cycle itself.