It is associated with the production of eggs and preparing the uterus for the implantation of fertilised eggs. The menstrual cycle occurs over a period of about 28 days. The changes during the cycle are due to four hormones, progesterone, oestrogen, FSH (follicle stimulating hormone) and LH (luteinising hormone).
Examples include wood and paper. Combustible liquids have a flashpoint at or above 100 degrees F but below 200 degrees F. This definition does not include mixtures containing one or more components with a flashpoint at or above 200 degrees F. This group of liquids can also be identified by class.
Paper can also be made entirely of grass and leaves as well, in fact, that's how most paper was made until the 20th century! You must cut the vegetation in small pieces, soak it in caustic soda to digest, strain it, and blend it to a pulp. Then pour it on the press. After it dries, you can proudly say, This paper contains no trees!