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.
If you need to take a GRE Subject Test, make sure you schedule this test at least 6 weeks in advance. These tests are only given in November, December, and April. Plan ahead in case you need to re-take this test. Take the GRE when you have prepared and are confident in your ability to do well.