The cell membrane to control what enters and leaves a cell. which of these substances is constantly moving in and out of the cell

The cell membrane helps to control what enters and leaves a cell. The substance which accounts for two-thirds of a cells mass is water which would be water

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.