was this movie based on a book?
Yes, it is based on "The Hunger Games" trilogy of novels
The Hunger Games (film series)
The Hunger Games film series is composed of science fiction dystopian adventure films, based on "The Hunger Games" trilogy of novels by the American author Suzanne Collins. 
when does katniss sing the hanging tree in the movie UNANSWERABLE from which movie is this? "The Hunger Games" what is the character's full name? Katniss Everdeen what is her name in real life? Jennifer Lawrence who composed the song? James Newton Howard
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The Hunger Games (film series) [SEP] Introduction
The Hunger Games film series is composed of science fiction dystopian adventure films, based on "The Hunger Games" trilogy of novels by the American author Suzanne Collins. The movies are distributed by Lionsgate and produced by Nina Jacobson and Jon Kilik. The series feature an ensemble cast including Jennifer Lawrence as Katniss Everdeen, Josh Hutcherson as Peeta Mellark, Liam Hemsworth as Gale Hawthorne, Woody Harrelson as Haymitch Abernathy, Elizabeth Banks as Effie Trinket, Stanley Tucci as Caesar Flickerman, and Donald Sutherland as President Snow. The first three films set records at the box office. "The Hunger Games" (2012) set records for the opening day and the biggest opening weekend for a non-sequel film.