I think this is too complicated of an answer to the question of why cereal grains lead to the creation of city states. IMO, the reason is much simpler: grains a

I think this is too complicated of an answer to the question of why cereal grains lead to the creation of city states. IMO, the reason is much simpler: grains are more economical than roots and tubers. By a lot. Based on data from my local super market, here are the amount of calories that some of these foods provide for $1: - Flour: 4,252 - Russet Potatoes: 1,437 - Yams: 540 I don't know why this is exactly, but my hunch is that it has mostly to do with spoilage. Specifically, that grains essentially do not spoil. The cited expert is also wrong, if I'm not mistaken, about the lack of civilizations born of on a staple other than cereal grains. The New World civilizations (Aztec, Inca, Mayas) did not have access to cereal grains. Their primary staples were potatoes (South America) and corn (Central America). --- FYI, I've done some work quantifying food costs, which are, IMO, a fascinating lens through with to view the world. If you want to dig in deeper, here's the Google sheet: https://docs.google.com/spreadsheets/d/e/2PACX-1vSo8XQrIKZ8GnNq2ALLmgD6J7JD78RQiyP5vYomGp8n_hZrHlhcbjAjyhbfUYSYk4UcW5Tf5Ek2jR-Y/pubhtml https://docs.google.com/spreadsheets/d/e/2PACX-1vSo8XQrIKZ8G.... I think the tabs labeled Food Chart and Category Range Chart are the most interesting (everything else is supporting calculations).