20 ! which civilization was located in central mexico, near present-day mexico city? inca aztec olmec maya

i'd assume india mainly because of how isolated japan was.   plus it is a whole china away.

most people now work in jobs where they do one  kind  of work; they are carpenters, bankers, cooks, mechanics, and so forth. likewise, most  businesses produce  only certainkinds  of  goods  or  services, such as cars, tacos, or gardening  services. this feature of  production  is known as specialization.