Answer
Scientists quickly replicate DNA with a polymerase chain reaction (PCR).
Work Step by Step
1. The PCR heats up to $94^{\circ}C$ and the hydrogen bonds holding the double-stranded helix together is broken.
2. The PCR cools to allow primers to bind to DNA. This also prevents DNA from reannealing
3. The PCR reheats and TAQ polymerase duplicates the DNA strands.
4. In the end, the DNA is duplicated
