And it will develop that skin layer as well as the ears, the nails and the hair. And not only that, because this blue layer, notice it will eventually move inside. It also forms the nervous system, the brain, as well as our spinal cord. And this green layer which is found on the inside will form our digestive system. It will form the epithelial layer of our digestive system as well as the lungs, the liver, the pancreas and the bladder. Now this structure develops into the umbilical vesicle.