Nina investigates what bellybuttons are for, with the help of Luke, her sight neuron.

Experimenters Izzy, Khalil and Leni-Rae visit Nina in her lab and discover that everyone has a bellybutton in the middle of their tummy... and so do lots of animals. Next they go to see a baby growing inside its mummy's womb and discover that it is joined to its mummy by something called the umbilical cord.

Back at the lab, they find out that when a baby is in its mummy's womb, it can't eat, drink or breathe on its own. They do an experiment to see how the baby gets all of the food, water and air it needs through the umbilical cord. Nina explains that when the baby is born, it doesn't need the cord any more so the doctor cuts it off. And the little bump that's left over is the bellybutton! Show less