Self-study
Chemist: Support The molecules of a certain weed-killer are always present in two forms, one the mirror image of the other. ███ ████ ██ ███ ████████ █████ ██████ █████ ███ █████ ███ ██ ██████ ██ █████ ██ █ ███████ ███ █████████████ ██ ███ ███████████ ██ █ █████ █████████ ██ ███████ ██████████ ██ █████ ██ ███ ███ █████ ██ ████ ████████████ ██ ███ █████ █████ ██ ████ ██████ ██████ ███████ █████ ████ ██████████ ████ ███████ █████ ███ █████████ ██ ███ ████ ██ ███ ██████ █████ ████ ██ ███ ████ ██ ███ ███████ ██ ████ ███████████ ███ ████████ ███████████
Summarize Argument
The chemist concludes that the data on the weed-killer's effects is likely misleading. She supports this by saying that the weed-killer’s molecules are present in two forms: one kills weeds, while the other doesn’t. The weed-killer’s effectiveness depends on which form is more concentrated in the soil, and this can vary a lot due to local soil conditions, which usually favor the breakdown of one form or the other.
Notable Assumptions
The chemist concludes that the data is misleading without explaining how it was collected. She assumes that the research on the weed-killer fails to account for the variability in local soil, ignoring the possibility that it might have been conducted in representative local conditions.
21.
Which one of the following, ██ █████ ████ ███████████ ███ █████████ █████████
a
In general, if ███ █████████ ██ █ ███████████ ███ ██████ ███████ ██ ███ ██████ ████ ██ ██ ██████ ████ █████ ███ ██████ ██ ███ ██ █████ ███ █████ ███ ██████████ ██ ███ ██████
The chemist’s conclusion is about the reliability of the data; we need an answer choice that suggests that the data is indeed misleading. (A) simply reinforces the fact that one of the weed-killer’s molecules kills weeds and the other doesn’t.
b
Almost all of ███ ████ ██ ███ ███████ ██ ███ ███████████ ███ █████ ████ ██████████ ███████ ██ █████ ████ █████ ██ ███ █████████████ █████████ ███ ███████ ████████████ ██ ███ ████ ███ ███████ ██████ ██ █████ ████ ██ ████ █████
This suggests that the data is indeed misleading. If the data comes from lab studies where both molecules are equally concentrated and likely to break down, it doesn't reflect how the weed-killer works in local soil, where one form usually breaks down more than the other.
c
Of the two █████ ██ ███ █████████████ ██████████ ███ ███ ████ █████ █████ ██ █████ ██ ████ █████ ████ ██████████ ██ ██ ███ ████ ████████████ █████
Even if the weed-killing molecule is more concentrated in most local soil conditions, this tells us nothing about whether the data is misleading. Did the data account for the fact that this molecule is more concentrated in most local soil conditions?
d
The data on ███ ███████ ██ ███ ███████████ ███ █████ ████ ███████ ██ ███ ███████████ █████ █ ███████ ██ ████ ██████████ ███████ ██ █████ ██ █████ ███ ███████████ ██ ████████ ████████
This weakens the chemist’s argument. If the data was drawn from studies that used a variety of representative local soil conditions, then it’s less likely that the data is misleading.
e
Data on the █████████████ ███████ ████ ████ ██████ ██ ███ ███████████ ██ ███ ███████ ██ ████ ███ ██ ███ ███ █████ ██ ███ █████████████ █████████ ████ ██████ █████████ ██ ███████████
It’s true that data that examines just one form of the molecule is likely misleading. However, we don’t know if the data in the argument makes this mistake. It might examine both forms, in which case (E) doesn’t tell us anything about its reliability.