endocrine
Yes
the Endocine system.
It is important to know the roles of each system in the body. The reproductive and the endocrine system is the cause of the onset of the menstrual cycle.
Usualy somewhere between 11 and 15.
Hormones are responsible for the onset of menses. When the body produces enough hormones, the menstrual cycle begins.
Menarche
Menarche
Menses is the commonly used term for menstrual cycle. Monthly periods is another commonly used term.
menarche; 12
MENSTRUAL CYCLE
A young lady's menstrual cycle is called a period.