The industrial revolution led to increase in child labor. The children were maltreated, overworked and underpaid. They worked from 12 to 14 hours a day and were given a total of one hour break only. The children were beaten and verbally abused and punished when they could not meet their quota. Orphans were treated like slaves. They were not paid at all. In 1833 the Factory Act was passed by Parliament. Working hours for children were set according to their ages but not to exceed 12 hours. No children below the age of 9 were allowed to work. The children had to attend school for at least 2 hours a day. Officials were appointed to make sure that the Factory Act was not violated.
The direct cause of WWI was the assassination of Archduke Franz Ferdinand at Sarajevo on 28 June 1914. However historians feel that a number of factors contributed to the rivalry between the Great powers that allowed war on such a wide-scale to break out. I'm not sure who the assassin was.