Glycerin. Glycerin is an ingredient that can be found in many beauty products because of its moisture locking properties. It is a form of sugar alcohol that is available naturally in vegetable oils and can also be the byproduct of soap making.
Definition of wheel and axle : a mechanical device consisting of a grooved wheel turned by a cord or chain with a rigidly attached axle (as for winding up a weight) together with the supporting standards
So In general axle shaft is on which the hub of the wheel is mounted. there should essentially be two rear axles in a vehicle, for each of the left and right wheel/s (hub) In a rear wheel drive, on side on the axle is attached to the differential assembly and the other side is attached to the hub.