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.
Yes, 3 months are sufficient to prepare for the GRE, provided you have a basic proficiency in English language and Quantitative ability sections, respectively. For the verbal ability you must adopt a two-pronged strategy. Primarily, you should try and bolster your vocabulary.