The Centers for Disease Control and Prevention estimates that 76 million cases of foodborne illness occur in the U.S. each year; 5,000 are fatal. Most of these illnesses are caused by a variety of bacteria, viruses, and parasites and the remaining are poisonings triggered by harmful toxins or chemicals. To Jack Guzewich, a foodborne disease…

Two science questions are answered: (1) How can someone have one brown eye and one blue eye?, and (2) Why are magnets attracted to some metals, but not all metals? It is very rare that a human will have two irises of different colors. This condition, heterochromia, can be a normal variant or the result of an ocular disease. Heterochromia can…