The simplest life-forms on Earth have just one cell. An example of a one-celled life-form is a bacterium. These species of bacteria all cause diseases in humans. But many bacteria are not harmful, or even helpful.
Mathematicians had the Chalkboard Math Clock, engineers had the Graph Paper Equations Clock, and now chemistry majors and nuclear scientists have the Chemistry Clock. Each number from one through twelve on the clock face uses the elemen