A period typically follows a 28 day cycle.
one week
It's another way of saying an infinitely long period of time. For ever.
One which sets out to study a group of subjects over a long period.
Premium period
About once every 28 days. However, there may be differences between one woman and another, and between one period and another for the same woman.
From the beginning of one period to the beginning of another period is anywhere from about 20 to 35 days; it varies from person to person.
Evolution
it depends from one girl to another. it may take place 10 days to 1 day before your period
I have had three children and the period after birth lasted around 3 weeks. If you breast feed your baby you will probably not have another period after this one until you stop breast feeding.
instead of long period of time, you can use phrases like:a long terma long spella phaseyou can even use the word tenure if it suits the situation.
That is called "anachronism," where something from one time period is placed or shown in another time period where it does not belong.
it does not have one
Photosynthetic producers
changing from one period to another
Mainly through gravity - the bodies attract one another. This means that gradually, over a long period of time, the gravitation of one planet can change the orbit of another planet.
one week
About 4-10 days