Before developing a hierarchy in classification, we need to decide which characteristics should be used as the basis for making the broadest divisions. Then we should pick up next set of characteristics for making sub-groups. This process must continue and each time new characteristics should be used. The characteristics that decide the broadest divisions among living organisms should be independent of any other characteristics. For example, nature of cell and form of the body is considered to classify organisms into broad divisions. The characteristics in the next level should be dependent on the previous one that will decide the subsequent divisions of the groups.