Changes at puberty:
(i) Sudden increase in height and weight.
(ii) Broadening of shoulders and widening of chest in boys. In girls, the region below waist becomes wider.
(iii) In boys, under the influence of hormones, the larynx becomes prominent, the vocal cords become longer and thicker. These changes cause the voice to become hoarse.
(iv) Appearance of hair in areas such as underarms, face, hands, and legs.
(v) Appearance of acne as a result of excessive secretion of oil from skin.
(iv) Testis grows and starts producing sperms in males, whereas in females, the ovary enlarges and starts producing matured eggs.