The correct answer is 1 and 3 only. Key Points The process of formation of a mature female gamete is called oogenesis which is markedly different from spermatogenesis. Hence statement 1 is correct. Oogenesis is initiated during the embryonic development stage when a couple of million gamete mother cells (oogonia) are formed within each fetal ovary; no more oogonia are formed and added after birth. These cells start division and enter into prophase-I of the meiotic division and get temporarily arrested at that stage, called primary oocytes. Each primary oocyte then gets surrounded by a layer of granulosa cells and is called the primary follicle. A large number of these follicles degenerate during the phase from birth to puberty. Therefore, at puberty, only 60,000-80,000 primary follicles are left in each ovary. The primary follicles get surrounded by more layers of granulosa cells and a new theca and are called secondary follicles. The secondary follicle soon transforms into a tertiary follicle which is characterized by a fluid-filled cavity called the antrum. The theca layer is organized into an inner theca internal and an outer theca externa. It is important to draw your attention that it is at this stage that the primary oocyte within the tertiary follicle grows in size and completes its first meiotic division. It is an unequal division resulting in the formation of a large haploid secondary oocyte and a tiny first polar body. The secondary oocyte retains the bulk of the nutrient rich cytoplasm of the primary oocyte. The tertiary follicle further changes into the mature follicle or Graafian follicle. Hence statement 2 is not correct. The secondary oocyte forms a new membrane called zona pellucida surrounding it. Hence statement 3 is correct. The Graafian follicle now ruptures to release the secondary oocyte (ovum) from the ovary by the process called ovulation. [ alt="5ff5a59c2895331682b1c1e1 16502170309101" src="//storage.googleapis.com/tb-img/production/22/04/5ff5a59c2895331682b1c1e1_16502170309101.png" style="height: 228px; width: 350px;">