But first, let's begin by discussing the early process known as gastrolation. So during early embryological development, we have a process known as gastrolation that takes place. So we have the Blastocyst implanticon cells onto the endometrium, the lining of the uterus and then gastrolation takes place and gastrolation produces the three different germ layers. So let's take a cross section of the gastrola stage of embryological development. We get the following diagram. So let's begin with these out of those cells known as the Trophy Blast cells.