The purpose of all topic sentence, depending on it's location, is to:

The purpose of all topic sentences is to announce what the paragraph will be about.  Besides all topic sentences have to be related to the thesis statement in order to achieve unity and focus in a text. A topic sentence generally appears in the first or second sentence in each body paragraph and serves to unify the content of the paragraph. Paragraph unity should be  accomplished if all the paragraph sentences are related to the topic sentence. When the paragraph contains restated ideas from the whole text, the topic sentence is placed at the end as a concluding statement.

citizens are given 25 years of life to prove their worth to society; if they fail to do great things

femininity is conveyed through bernice's personality. she doesn't act how the other girls act and everyone thinks she is weird. she learns how to act in a way that was considered femininely appropriate at the time. she becomes so popular but her attempts to be liked end up backfiring when she is pressured into bobbing her hair. the author wrote that bernice cut off her cousin's hair in revenge for tricking her to cut her hair. this was the authors way of trying to change the way feminine is defined and the way women are expected to act.