Disaccharides are a class of sugars composed of two monosaccharide units joined together. The best known example is sucrose , which is composed of a glucose molecule joined with a fructose molecule. Likewise, lactose is composed of a glucose unit with a galactose unit, and maltose is a disaccharide composed of two joined glucose units. Energy is the capacity to do work. It can be manifested as heat, motion, electricity, light, etc., all of which forms are convertible into each other.
Fats are a natural oily or greasy material present in animals as a form of energy storage.
These fats tend to be solid at around normal body temperature. Their counterparts in plant life are called oils which are very similar in function and in chemical composition, but are generally liquid at around body temperatures. Chemically they are fatty acid esters of glycerol. The most vulnerable are sugars and cooked starches. Some uncooked starches are slow to ferment, and substances such as cellulose are very resistant to attack by most micro-organisms.