Question

What was needed before cities and complex civilizations could develop in the Americas?
1) plenty of land
2) a surplus of food
3) a large population
4) access to precious metals

Answer 1

None of the above . The sine qua non for cities is good transportation. That's the only way food and water can be brought into the city, and goods and trash shipped out, fast enough and over a broad enough area of the surrounding countryside, to avoid the city suffocating.

Transportation naturally limits the sizes of cities. That's why cities with ports or on rivers grew bigger first, and why the size of European cities (developed in the age of the horse) are smaller than American (developed in the age of rail), and Western American cities, developed in the age of the car and airplane, are enormous (the Los Angeles urban area being nearly 100 miles across).

Answer 2

Carl gave a great answer, but out of those choices it would have to be 2) a surplus of food.

Answer 3

2.

Answer 4

Do you folks always have to deal with this? Multiple-choice questions in which all of the answers are wrong, and then you have to either pick the least wrong or try to guess what the instructor had in mind? What an appalling statement on modern education. Sounds like the computer-scored multiple-choice test is a complete curse.

Answer 5

The choice surplus of food is not the least wrong answer. The question is asking about civilizations like the Aztecs, Incas, Mayans, etc. Notice how the question is not simply asking about North American development in the past 2 or 3 centuries but rather development in the America[S].

However, I have to agree with you on multiple-choice tests; they, along with the modern education machine, are abominations.

Answer 6

My examples from modern North American history were merely illustrative. Do you really think the factors that cause cities to form in the 18th century differ radically from those that cause them to form in the 6th? That seems a priori unlikely.

Anyway, I disagree that surplus of food -- and I am not even entirely sure how one would define or measure that -- is related in any obvious way to the formation of cities, i.e. the concentration of people in specialized communities. Why would it be? For any reasonable hypothesis about why it would be -- e.g., that cities are founded for trading, and trading is only possible when you have something in surplus, and the most obvious thing an agrarian primitive society can have in surplus is food -- there is an equally reasonable hypothesis running the other way -- e.g. that cities are founded for good defense and such a purpose becomes even more urgent when there isn't enough food (or other resources) to go around, so that armed struggle over them is more likely.

There is, however, no question, from purely mathematical grounds, that concentration of people absolutely requires a certain minimum velocity in and out of goods. For example, a typical household use of water is 50 gallons per person per day. That is the amount of rain that falls on average on 56 square meters of land in the vicinity of Rome. To supply the water needs of a city of 100,000, you need to transport the rain from 5.6 million square meters of land (1400 acres) into the city every day. You need to transport an equal volume of waste water out of the city every day. This puts minimum transportation needs on the formation of the city. Similar limits are imposed by the needs of transporting in food, building materials, raw materials for industry, and for transporting out garbage and manufactured goods.

Who knows why people build cities? That is a deep social psychological question. But plain physics puts limits on whether they can build cities, based on their transportation technology.