Our bodies are made of cells, tens of trillions of cells. They all have particular roles and functions in the body, from digesting food, to producing hair, to hunting down pathogens. But all of this incredible complexity started as just a single cell. Gila, from Israel, asked CrowdScience to find out how the development of incredible structures, and systems in the body are coordinated by the cells. Are cells communicating? How do cells know what they should be doing? To find out, Geoff Marsh meets a Cambridge researcher uncovering the first cell division in our lives, and peers into a fertile chicken egg to see the developing embryo as it grows a limb. CrowdScience finds out why scientists like Dr Megan Davey use chickens to understand the development of human fingers and investigates how individual cells with the same DNA manage to choreograph a dance of cell replication, movement and communication to create our bodies in all of their complexity. Presenter: Geoff Marsh Producer: Rory Galloway (Photo: Cells grouped together. Credit: Getty Images)