Glucose is an important fuel released from sugar. Glucose belongs to carbohydrates. Glucose is produced by the digestion of other carbohydrates. The animal needs fuels to function. The fuels are a source of energy. The animal absorbs glucose into the blood, and through the blood, it reaches tissues that can burn glucose. The animal's body ensures that the supply of glucose remains constant. Diabetes occurs when the regulation of blood sugar levels is disturbed.