Polymerase Chain Reaction (PCR)

To those who know everything about PCR, here's a vid for you people! These people look really passionate about PCR!! To those who don't know, PCR is a process where copies of a specific sequence of DNA are made. Why do they need to make that specfic sequence?? Well, you see, sometimes say in a crime scene, say you find a strand of hair. And then you gotta figure out whose hair is that by looking at its DNA sequence. But what happens if something goes wrong with that sample? Or you might need to conduct more tests, but you only have one DNA sample, which is the hair. So, there's when PCR comes in!