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!
decline, ( depends on what you are talking about, i'm thinking more like women are getting less and less populated)
The answer is 1) Eating disorder.