(a) (i) There is a sudden increase in the height of both boys and girls during puberty.

(ii) Development of sex hormones also take place in both boys and girls during puberty.

(b) Changes that place only in boys during puberty are:

(i) Growth of hairs on chest.

(ii) Enlargement of voice box which leads to much deeper voice

(c) Changes that place only in girls during puberty are:

(i) Mammary gland enlargement

(ii) Menstruation.