lovelyloser04 lovelyloser04 01-01-2019 Social Studies contestada What did Upton Sinclair do to prepare for writing The Jungle? Select all that apply. A He studied details about working in a slaughterhouse. B He studied details about the home lives of slaughterhouse workers. C He opened a slaughterhouse to see firsthand how it worked. D He saw a documentary film about slaughterhouses in a local theater.