What effect did upton sinclair’s novel have on working conditions for immigrants in the meatpacking plants?

It showed how terrible working conditions were for the immigrants working in the industry. which is good because it opened the eyes of the public as to what was going on in the meat packing plants which was utterly disgusting and thus forcing the meat packaging companies to start having better working conditions and have better and much more sanitary ways of packing meat

Spanish conquistadors demanded labour from natives.