the Agricultural Revolutionthe Industrial Revolutiondevelopment of collective bargaining
Agricultural revolution. Although I too cringe at this answer. Multiple choice always seems to encourage dogma.
Sorry, are those the options, or your guesses? I was going to say that the increased efficiency that came with farm labor-saving machinery, and mechanization more generally, led to plots of land growing in size and requiring less people to reap the harvest. Ultimately, this led to a huge influx of labor (people) into the cities looking for work (and eventually, the industrial revolution). Edit: Thank you for the clarification. As the other poster has said, the obvious dumb answer is the AR, but there were several other factors that contributed to that revolution other than mechanization, so it's not entirely correct. One could also argue that mechanization was a major stepping stone towards the IR.
