The study of the relationships of living and non-living things in an environment is the complete definition of ecology. Many times relationships are so important that if they didn't exist the living thing would suffer or die. This kind of relationship is called a dependent relationship . The relationship between parents and young children is like this. If parents do not take care their children it is possible that the children will suffer.
Children are dependent upon their parents.
When parents grow older they often also need help from their grown children. For this reason, during their lives children and parents are said to be interdependent upon one another. They have an interdependent relationship because they need each other. Sometimes a relationship exists that is mutually benefiting to both living things involved. The relationship between parents and children that live together is usually mutually benefiting because parents help their children to live and in return children help their parents to live.