Ape teeth. Coloured scanning electron micrograph (SEM) of sections through an ape's jaw, showing two fully formed teeth and an unerupted tooth (bottom right). The crown (visible part) of a tooth is covered in a layer of enamel, the hardest substance in the body. Beneath this is dentin (brown and yellow), composed of mineralised connective tissue. Pulp cavities (black) in each tooth contain the nerves and blood supply. The pulp cavity extends from the crown and into the root canals. The teeth are embedded in the alveolar bone of the jaw. Magnification: x8 when printed at 10 centimetres tall.