A day is based on the TIME it takes the Earth to rotate
Fats and Oils. The triesters of fatty acids withglycerol<span> (1,2,3-trihydroxypropane) compose the class of lipids known as fats and oils. These triglycerides (or triacylglycerols) are found in both plants and animals, and compose one of the major food groups of our diet.</span>