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.
In addition to the General Test, there are also six GRE Subject Tests testing knowledge in the specific areas of Biology; Chemistry; Literature in English; Mathematics; Physics; and Psychology. The length of each exam is 170 minutes.