Define (i) menarche, and (ii) menopause.
Menstruation: -The cycle of events taking place in female reproductive organs under control of sex hormone, in every 28 days and marked by bleeding or menstrual flow is called menstruation.
Menarche:-
It is the stage of initiation of menstruation in the life of a female girl. it generally occurs at an age of 11-13 years. It refers to the beginning of the reproductive phase in girls.
Menopause:-
It is the stage at which menstruation stops In the life of women . it occurs in women at the age between 45-50 years. It refers to the end of the reproductive phase in the women.