Answer:
Puberty begins when the pituitary gland secretes sex hormone in the blood.
Explanation:
Puberty begins during adolescence when the pituitary gland secrete sex hormones in the blood. Sex hormones that are released by the pituitary are luteinizing hormone(LH) and follicle-stimulating hormone(FSH).
In males, FSH stimulates sperm production and in the female, it stimulates the growth of ovarian follicle in which ova develops. LH in female stimulate the release of ova from Graafian follicle and also stimulate secretion of progesterone hormone and in males, it stimulates testes cells to produce testosterone.
Secretion of progesterone, estrogen in females and testosterone in males bring sexual and physical changes in them. Therefore Puberty begins when the pituitary gland secretes sex hormone in the blood.
