Why did manufacturers hire children to work in their factories?

Which of the following groups was from new york but felt ostracized by their neighbors because of their religious beliefs? question 40 options: irish catholics germans chinese immigrants mormons

Which physical feature minimizes population density in northern africa?

The rise of advertising in the 1920s. i am good with seeing how advertisements shape the roaring twenties and how it developed a new way of life through modern days. but i am not sure what the details of advertising in the 1920s were. if possible can you send me links (preferrably credential links) to sources that maybe show like the first company to start advertising through the radio, how advertising benefits (statistics graphs), etc.