Humans begin their existence as a single undifferentiated cell and proceed to become a highly complex and organized system consisting of specialized cells (liver, skin, brain, blood, etc.). This change BEST exemplifies the principle.

Orthogenetic

Explanation:

The Orthogenetic principle of development was put forward by Heinz Werner, in the year 1975.It is a biological principle of development. This principle of development states that all the aspects of the functioning of a living organism develop progressively from a less differentiated state to a more differentiated state. Besides differentiation, there is also hierarchic integration and articulation of functioning such as perception, cognition, etc. This leads to the development of more complex forms from a simple form.Therefore, a single undifferentiated cell giving rise to the complex organized system is an example of the orthogenetic principle.