Final answer:
Primordial germ cells give rise to either spermatogonia or oogonia based on genetic signals. During oogenesis, a primary oocyte will resume meiosis at adolescence, and if fertilized, the secondary oocyte will complete meiosis II to form a zygote which implants in the uterus.
Step-by-step explanation:
Primordial Germ Cells and Their Development After Arising
After primordial germ cells arise, they will differentiate based on the presence or absence of the SRY gene. With the SRY gene, these cells develop into spermatogonia, starting the process of spermatogenesis. In absence of the SRY gene, the germ cells give rise to oogonia and eventually primordial follicles in the primitive ovary. The process of oogenesis begins with a primary oocyte, which is arrested in the prophase stage of the first meiotic division. At adolescence, hormonal signals will stimulate the primary oocyte to complete the first meiotic division, forming a secondary oocyte and a polar body. The secondary oocyte is then arrested at metaphase II and will only complete meiosis II if fertilization occurs, resulting in a zygote that will begin its journey to the uterus for implantation.