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 Total Time: The computer-delivered GRE takes 3 hours and 45 minutes for the average student.  Experts recommend sitting for the GRE exam one year prior to entering graduate school. This allows for ample study time and the option to retake it if desired.