Final answer:
In Jane Austen's 'Pride and Prejudice', the passage at the end of the first chapter where Austen describes Mrs. Bennet's unchanged personality after her daughters' marriages exemplifies her as a 'flat' character, whereas Elizabeth is shown as a 'round' character with complexity and development.
Step-by-step explanation:
In Pride and Prejudice, the passage that most strongly supports the characterization of Mrs. Bennet as a "flat" character can be found in the summary provided by Jane Austen at the end of the first chapter of the novel. This passage indicates that despite the marriages of her daughters, Mrs. Bennet's personality remains largely unchanged, highlighting her as a flat character. In contrast, Elizabeth, as a central character, exhibits a depth that categorizes her as a "round" character, capable of development and complexity over the course of the story.
The passage reads:
"Happy for all her maternal feelings was the day on which Mrs. Bennet got rid of her two most deserving daughters. With what delighted pride she afterwards visited Mrs. Bingley and talked of Mrs. Darcy may be guessed. I wish I could say, for the sake of her family, that the accomplishment of her earnest desire in the establishment of so many of her children, produced so happy an effect as to make her a sensible, amiable woman for the rest of her life; though perhaps it was lucky for her husband, who might not have relished domestic felicity in so unusual a form, that she still was occasionally nervous and invariably silly."
Jane Austen uses this passage to illustrate Mrs. Bennet's static character traits, in contrast to Elizabeth's growth over the course of the novel.