Progesterone is a hormone released by the corpus luteum in the ovary. It plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy. It may also be involved in the growth of certain cancers.
I've been following various people's posts about the GRE for 10 months now. Some people don't study at all for the GRE, some study for a weekend, the average is about 2 to 3 months, and some study for a year or more.
1 This allows for ample study time and the option to retake it if desired. 2  GRE scores are good for five years; some take the exam their first year of undergrad when the SAT is fresh in their minds.  Students can take the GRE up to five times in one year, with gaps of at least three weeks between each test.