How did john spargo get the information for his book the bitter cry of children?

The correct answer for this question, actually, after reading the whole of the book written by John Spargo, would be: 3. He went into the mines undercover and discovered the true conditions that children experience working in these mines.

Explanation:

"The Bitter Cry of Children" is a really heartwrenching narration of the research work done by socialist John Spargo, and which was first published in 1905. This entire book is dedicated to the horrific reality of child slavery, poverty, and child malnutrition, which is the cause of furthering poverty. What Spargo sets out to do, is gather first-hand information on the factory system in America, and comes to live the experiences of children in these factories. He goes into textile industries, cotton mills, glass-producing factories, and most of all, he enters the mines (coal mines, and others) and witnesses first-hand what children have to go through in different states as they work inside these mines. He particularly narrates an experience he has in a coal mine, trying to do the work a 12-year old boy had to do, and he notices that if he had been the one working 16 hours a day, he would have never survived. This is why the answer is 3.

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what was the significance of the plessy vs ferguson ruling and jim crow laws

answer the impact. plessy v. ferguson allowed 'separate but equal, also known as segregation, to become law in the united states