(a) A testosterone is the hormone produced in the testes that stimulates the development of secondary sexual characters in males.
Its important functions are :
(i) Development, maturation and functioning of the male accessory sex organs like vas deferens and seminal vesicles.
(ii) Stimulate muscular growth, growth of facial hair, low pitch voice, etc., sperm production.
All these activities are hindered in the absence of testosterone.
(b) Fertilization takes place in ampulla region of fallopian tube and zygote gets implanted in the uterus.
(c) Embryo is present in the womb of a mother where it is connected with the uterine wall of mother by placenta. The foetus receives oxygen, nourishment and other life supporting things from mother through this placenta.