John and Mary are husband and wife and both are working people.
Mary goes to gym after office because she thinks that John, her husband comes to home late from office. And John works late in the office because he thinks that Mary goes to gym for exercising after office.
Both of them have their own reasons for their beliefs and both reasons can be considered true.
Thus, John and Mary involves punctuating principle of organizing and imposing structure.
Animals get the nitrogen they need by eating plants or other animals that contain nitrogen. When organisms die, their bodies decompose bringing the nitrogen into soil on land or into ocean water. Bacteria alter the nitrogen into a form that plants are able to use.
