Answer:
loyal slave he gained as loyal slave
What caused industrial psychologists to begin working with the military was <span>U.S. entry into WWI.
After years of upholding its isolationist policy of not getting involved with any wars it has nothing to do with, the US actually decided to go back on that decision and join the WWI. This is why many psychologists started working with the army in order to help the soldiers.
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The Industrial Revolution transformed economies that had been based on agriculture and handicrafts into economies based on large-scale industry, mechanized manufacturing, and the factory system. New machines, new power sources, and new ways of organizing work made existing industries more productive and efficient