What is a smell? A smell is the sensory response to chemicals known as odourants, which are carried by the air around us. Both single chemicals and complex mixtures of many chemicals produce the sensation of a single smell or odour.
The last time you opened wide, did you ever imagine that you were opening the door to what is essentially home to thousands of bacteria? Christa Favot introduces you to what's really living in your mouth, including plaque bacteria and biofilms.
Chris Smith describes how cloning, occuring naturally in your body continuously, will have produced literally metres of new - cloned - DNA, by the time you
finish this article, as cells divide to replace themselves, repair injury or help us grow.