(a) Define Puberty. List any two changes seen in boys at the time of puberty. (b) Why are testes in human males located outside the abdominal cavity in scrotum? (c) List any three techniques of contraception used by humans. Which one of these is not meant for males? OR (a) Name the part performing following functions in human female reproductive system: (i) production of eggs (ii) site of fertilization (iii) site of implantation (iv) entry of the sperms (b) What changes are observed in the uterus: (i) subsequent to implantation of zygote and (ii) if an egg does not get fertilized?

(a) Puberty is the period of life when the sexual organs begin to mature and become capable of reproducing sexually. Two changes seen in boys at the time of puberty are: (i) Growth of hair in the pubic region and other parts of the body. (ii) Deepening of the voice due to the enlargement of the larynx. (b) Testes in human males are located outside the abdominal cavity in scrotum because sperms are highly sensitive to temperature. The scrotum helps in maintaining the low temperature of the testes necessary for the production of sperms. (c) Three techniques of contraception used by humans are: (i) Barrier method (condoms) (ii) Oral contraceptives (iii) Intra Uterine Devices (IUDs) Oral contraceptives are not meant for males. OR (a) (i) Ovaries (ii) Fallopian tube (iii) Uterus (iv) Vagina (b) (i) Subsequent to implantation of zygote, the uterus prepares itself for the development of the embryo. The uterine wall thickens and the uterus becomes enlarged and more vascular. (ii) If an egg does not get fertilized, the uterus sheds its lining, and this leads to menstruation.