Joe

@Grumpy "Where hunger is ugly, where souls are forgotten / Where black is the color, where none is the number" - Bob Dylan, "A Hard Rain’s A-Gonna Fall"

@Shimmer It could also be referring to the nuclei of cells, in which chemistry plays a bigger part.

@John and biology doesn't involve chemistry? I don't follow your logic. Chemistry is involved in both the actions that take place in a cell nucleus, and, as Andrew says below, the actions that take place in an atomic nucleus. It may not be the best word choice, but it's not wrong.