1. Appendix to life

The appendix gets a bad press. It is usually treated as a body part that lost its function millions of years ago. All it seems to do is occasionally get infected and cause appendicitis. Yet recently it has been discovered that the appendix is very useful to the bacteria that help your digestive system function. They use it to get respite from the strain of the frenzied activity of the gut, somewhere to breed and help keep the gut's bacterial inhabitants topped up. So treat your appendix with respect.

Practically everything we experience is made up of molecules. These vary in size from simple pairs of atoms, like an oxygen molecule, to complex organic structures. But the biggest molecule in nature resides in your body. It is chromosome 1. A normal human cell has 23 pairs of chromosomes in its nucleus, each a single, very long, molecule of DNA. Chromosome 1 is the biggest, containing around 10 billion atoms, to pack in the amount of information that is encoded in the molecule.

It is hard to grasp just how small the atoms that make up your body are until you take a look at the sheer number of them. An adult is made up of around 7,000,000,000,000,000,000,000,000,000 (7 octillion) atoms.