The cities of Oldtown and Spoonville are the same in area and size of population. Since certain health problems that are caused by crowded living conditions are widespread in Oldtown, such problems must be as widespread in Spoonville.The reasoning in the argument is most vulnerable to criticism on the grounds that the argumentThe argument says: same area and same population implies same crowded living conditions, so the same crowding caused health problems must be equally widespread. The flaw is that overall density can match while actual crowding patterns differ a lot.
(A) presupposes without warrant that the health problems that are widespread in any particular city cannot be caused by the living conditions in that city
This misreads the argument. The argument explicitly says the problems are caused by crowded living conditions, so it is not presupposing they cannot be caused by those conditions.
(B) fails to distinguish between the size of the total population of a city and the size of the geographic region covered by that city
The argument does not confuse population size with land area; it explicitly uses both to imply density. The issue is what density implies, not mixing them up.
(C) fails to indicate whether average life expectancy is lowered as a result of living in crowded conditions
Life expectancy is irrelevant. The argument is about whether certain health problems are widespread, not about average lifespan.
(D) fails to distinguish between those health problems that are easily treatable and those are not
Treatability is irrelevant to whether the problems are widespread in the two cities.
(E) fails to take into account that having identical overall population density is consistent with great disparity in living conditions
This nails the flaw. Two cities can have the same overall population density but very different distributions of housing and crowding (one may have many overcrowded neighborhoods, the other may have more evenly spread or better housing). So the inference from “same area and population” to “same crowding related health problems” is weak.
That is the vulnerability.Answer: (E)