Write a summary of the plot of The Experiment. Include the setting, character, problem, events, and solution.

Unemployed Travis (Adrien Brody) enrolls in a psychological role-playing experiment, where participants assume the identities of inmates and prison guards in an empty jail, with the promise of a $1,000-a-day reward. Another participant, Barris (Forest Whitaker), embraces his correctional officer role with a vengeance, and before long, the prisoners find themselves at the mercy of their keepers. All the test subjects discover how easily violence and cruelty can manifest itself in human behavior.

Explanation:

quite an interesting way to teach topic sentences, because the answer to this question is the best definition of a topic sentence that one can present, it is as if answering the questions taught you how to do it, this is some real teaching, it is terribly well-done.

the topic sentence in this paragraph is:

topic sentences writers stay on track and keep a paragraph from becoming an aimless collection of sentences about an idea.

which incidentally tells you what a topic sentence should be.