In some cultures the engagement ring will be worn on the fourth finger of the right hand. The wedding band alone, or together with the engagement ring will be worn on the fourth finger of the left hand after marriage. It is automatically known, when you see a ring on the right hand that the young lady is engaged.If she is not engaged she can wear a ring with any kind of stone on her left hand.ngagement rings are different from wedding rings primarily in that they are worn before a legal or symbolic marriage ceremony. They are often bought before the wedding rings as well, although some people choose matching sets that are purchased together.
In chemistry, stereospecificity is the property of a reaction mechanism that leads to different stereoisomeric reaction products from different stereoisomeric reactants, or which operates on only one (or a subset) of the stereoisomers.he addition of singlet carbenes to alkenes is stereospecific in that the geometry of the alkene is preserved in the product. For example, dibromocarbene and cis -2-butene yield cis -2,3-dimethyl-1,1-dibromocyclopropane, whereas the trans isomer exclusively yields the trans cyclopropane.
Olfaction, along with taste, is a form of chemoreception. The chemicals themselves that activate the olfactory system, in general at very low concentrations, are called odorants. Although taste and smell are separate sensory systems in land animals, water-dwelling organisms often have one chemical sense.he sensory receptors of the accessory olfactory system are located in the vomeronasal organ. As in the main olfactory system, the axons of these sensory neurons project from the vomeronasal organ to the accessory olfactory bulb, which in the mouse is located on the dorsal-posterior portion of the main olfactory bulb.