Self-study
The higher a dam, the more exposed it is to forces that can cause it to collapse. ██ ███ ███████ ████████ ██ ████ █████ ████ ████ ████ ███ ████ ███ ██████ █████ ███ ███ ███ ██ ███ ████ ███ █████████ ████ ████ ████████ ██████ ███ ████ ██ █████ ████ ████████ ██ ████ ████ █████ ███ ██████ █████
"Surprising" Phenomenon
Taller dams are more vulnerable to forces that could cause a collapse, and most arch dams are very high, so why is it that shorter arch dams account for all of the recent arch dam collapses?
Objective
The correct answer must help explain why shorter arch dams have been the ones to collapse, despite the fact that the taller ones are subject to greater forces. The stimulus doesn’t provide information on how either type of dam is constructed or maintained, so it's possible that the taller dams are built to be more resilient, or that they’re better maintained.
12.
Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ████████ ████████
a
The higher a ███ ████ ███ ███ ███████ ███ ██████████ ████ ██ ████ ██ █████ ██ ██ ████ ████
The stimulus compares tall arch dams to short arch dams, so this is irrelevant. The correct answer must explain why short arch dams, rather than tall ones, have collapsed in recent years.
b
Arch dams are █████████ ████ ███████████ ███ ████ ██████ ██ █████████ ████ █████ █████ ██ ████ ██ ██████████ █████
The stimulus compares short arch dams to tall ones, so it's irrelevant whether arch dams are more complicated than other types. This doesn't help to resolve the paradox.
c
The larger the ██████████ ███ ████ ███████ ███ █████████ ██ ████████ ██ ██████ ███ █████████████
This explains why the taller arch dams haven’t collapsed. They may be subject to more risk, but if they’re constructed more carefully, it makes sense why they've stayed standing.
d
The basic engineering ██████████ ██████ ███ ██████ ███ ████████████ ██ ████ ████ ████ ████ █████ ███ ████ ████ ███ ██████
The stimulus is only discussing arch dams, so this information would apply equally to both short and tall dams. In other words, this doesn't explain why only shorter dams have collapsed recently.
e
Arch dams under ███ ██████ ████ ███ ████ ███████ ██ ████████ ████ ███ ████ ██ █████ █████ ████ █████ ███ ██████ █████
The stimulus compares short arch dams to tall arch dams; it doesn’t matter how their vulnerability to collapse compares to other kinds of dams. This doesn't resolve the paradox.