Answer:
a case study
Explanation:
A <em>case study</em> looks at all aspects of a particular case.
D
..........................................................................................................................................................................................................................................................................................
This means that there are steps or stages throughout one's life in which the mind and personality undergo changes. For example, one may take a step as a child going from rarely having their own thoughts and feeling to creating their own opinion. This would be a step that the person is taking.
Hope this helps!