Answer from "Bathy", an Evolutionary Biologist:
Bacteria are truly amazing organisms that we are just beginning to understand. One of the coolest aspects of bacteria is that they can grow on practically anything - different sugars, carbon dioxide, methane, and even poisonous compounds. Unfortunately, many people equate bacteria with germs when, in fact, most bacteria are not harmful to people and there are actually several kinds of bacteria living on and in our bodies which keep us healthy. Because of DNA sequences, we now know that all of life can be divided into three groups: bacteria, archaea, and eukaryotes (which includes plants and animals). Based on biochemistry and molecular biology, it looks like archaea and eukaryotes are more related ot each other than to bacteria, even though archaea are single-celled organisms like bacteria.

Thanks to Esther from Winter Hill Middle School for submitting this question!