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.
Yes
Usualy somewhere between 11 and 15.
It is controlled by the uterus. That is where the uterus lining is which causes the menstrual cycle
Hormones are responsible for the onset of menses. When the body produces enough hormones, the menstrual cycle begins.
purberty for girls around whenever they're in 6th grade
menarche; 12
You can't have a two day menstrual cycle. A menstrual cycle is the entire reproductive cycle, including ovulation and menstruation, so you can't possibly have a two day menstrual cycle. You may experience two day menstruation, or mid-cycle spotting for two days.
The menstrual cycle is the cycle of hormonal changes between your reproductive organs and brain that cause ovulation and in turn failing fertilisation causes menstruation. It is not possible for a menstrual cycle to last only two days.
Various things can happen to cause bleeding outside of the menstrual cycle. For example, it is possible for sex to cause bleeding.
The menstrual cycle is the reproductive cycle, as long as she is fertile she is always on her menstrual cycle. You can't tell where she is in her menstrual cycle unless she tells you.