Fats , oils , waxes and sterols are collectively known as lipidsand the true fats contain only carbon , hydrogen and oxygen
Election current because voltage is a measurement, information doesn't apply to all electrical devices and the wires within are usually copper bc it conducts and hardly ever will the wires be anything different because copper is cheap
The distance from one crest to another crest or from one trough to another trough is called wavelength. Hope it helps