I guess we have all seen the ads for bleach that claim they kill 99% of germs dead. Maybe you have wondered about the other 1%? Killing the last 1% may be harder than you think. Naively you might think that bleach just kills bacteria, and that’s the end of it. But scientists working on bacteria like E. Coli have found that the individual bacteria are surprising diverse, in the following sense. Consider a population of millions of E. Coli, and assume that they are all clones, i.e., are genetically identical. If they are all descendents of a single bacterium then this would be true. You might assume that these genetically identical clones would all behave identically, e.g., would all require the same dose of something nasty like bleach, to kill them.