What serious problems did people in the cities face in the mid 1800s
a. crime
b. fire
c. pollution
d. disease
e. all of the above

they remained in rural areas and worked at jobs such as lumbering or farming.

a is the final : )

the china one is last

explanation:

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.