Progesterone, which regulates cyclical changes in the endometrium of the uterus and maintains a pregnancy The letters α and β[18] denote absolute stereochemistry at chiral centers—a specific nomenclature distinct from the R/S convention[19] of organic chemistry to denote absolute configuration of functional groups, known birli Cahn–Ingold–Prelog priority rules. The R/S http://mozillabd.science/index.php?title=brandstrupbentzen9693