Physical, chemical and mathematical sciences follow a specific set of rules and regulations. They are governed by a set of laws such as the law of gravity, the laws of thermodynamics, the law of conservation of mass and so on. However, biological sciences, in the strict sense, do not follow any rules or regulations. The reason for this is that living organisms show a rich diversity that has resulted from mutations, genetic re-combinations and evolution. Biology is thus, regarded as 'a science of exceptions