In a girl child, the oogonium multiplies by mitosis in the foetal stage. The oogonium (p) undergoes the growth phase and gives rise to the primary oocyte (q). After the girl attains puberty, the primary oocyte undergoes first meiotic division to produce a large secondary oocyte (r) and the small 1‌st polar body. The polar body is degenerative in nature. During ovulation, the Graafian follicle rupture and releases the secondary oocyte. The secondary oocyte undergoes the second meiotic division in the fallopian tube resulting in the formation of ovum and a second polar body.