Answer:
outrage toward the meat-packing industry.
Step-by-step explanation:
President Theodore Roosevelt's first reaction to Upton Sinclair's "The Jungle" is best described as outrage toward the meat-packing industry.
The book by Upton Sinclair about the poor and unhygienic state of the meat industry brought about public outcry because the people were surprised and demanded healthy livestock. President Roosevelt was also shocked and incensed and he sent a team of investigator's to find out if Upton Sinclair's claims were true and they found out that the slaughterhouse conditions were far worse than originally imagined.