So when the female reaches puberty, a cycle begins known as the menstrual cycle, in which one primary oocyte will eventually undergo meiosis one to produce a secondary oocide which will remain frozen in metaphase II of meiosis until the process of fertilization. And during fertilization, meiosis II will be completed and aromature ovum, the excel, will be formed. So to see exactly what we mean by that, let's take a look at the following diagram. So this diagram describes a cross section of the ovary. So this is one of the ovaries of that female individual that has reached puberty. So let's suppose this is the ovary.