"A graph titled ""Hormonal Fluctuations Across the Menstrual Cycle"". The x-axis is labeled ""Day of Cycle"" and starts at 1 and continues to 28. The y-axis is labeled ""Hormone Levels"". A pink line indicates that progesterone is near baseline until about the 14th cycle day, at which point it increases. Progesterone peaks around day 21, and then returns to baseline by day 28. A red line indicates that estrogen is near baseline until about the 5th cycle day, after which point it increases to a peak around day 11 before briefly returning to baseline around day 14. Estrogen reaches a second peak around day 21, but remains lower than progesterone's peak. Estrogen returns to baseline around day 28."
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