How did Sinclair's The Jungle lead to reform?

Beginning in the late 19th century, many people became concerned with  

many social problems resulting from the industrialization period of  

the United States. People began to demand reform. The writing of the  

book The Jungleby Upton Sinclair was one of the most influential tools  

used to reform many American industries. In this book, Sinclair  

focuses on the unsanitary conditions and corruption that was involved  

in the Chicago meat packing industry. This book exposed so much information to the public that it even caused new legislation to be  

passed concerning the matter. This book also indicted slave wages and  

the poor treatment of immigrant workers. Sinclair was a socialist and  

argued that socialism was the only solution to the problem of abused  

men and women in America's policy of industrial capitalism. It shows a  

number of universal problems screaming for help.

Explanation:

the two colonies had the earliest laws mandating religious tolerance.