Opal is considered the birthstone for people born in October. Famous opals. The Olympic Australis, the world's largest and most valuable gem opal [citation needed], found in Coober Pedy; The Andamooka Opal, presented to Queen Elizabeth II, also known as the Queen's Opal
1 Carbohydrates â are required for energy. 2  Glucose, which is a monosaccharide, is the most essential source of energy in the body. 3  The brain works entirely on glucose alone. 4  When an immediate source of energy is required, glucose is converted into glycogen which is stored in the liver.
Carbohydrates and protein provide 4 calories of energy per gram while fat yields 9 calories per gram. Carbohydrates are broken down into glucose and absorbed into the bloodstream. Fat is a major source of stored energy and is held as a reserve in the body until we need it. Fat is the preferred source of energy for the heart. Protein is broken down slowly and is a longer-lasting form of energy.