Self-study
Before 1986 physicists believed they could describe the universe in terms of four universal forces. ███████████ ████ ██████████ ████████ █ █████ █████████ █████ ██ ██████ █████████ ███████ █████████ ██ ███████ ████ █████ █████ █████ ███████ ███ ██████████ ██ ███ ███████████ ██ █ ███████ ███████████ ██ ███ █████████████ ██████████ ███████ ██████ ████ ███ ███████████ ██████ ██████████
Summarize Argument: Phenomenon-Hypothesis
We don't have a clear conclusion from the author, but from the question stem we know we want to strengthen the argument that there is a fifth universal force. So we are taking the point of view of the scientists who suggested a fifth universal force based on the experiments they performed. The main evidence offered for this hypothesis is that a fifth force would explain the unusual phenomenon of smaller-than-expected gravitational measurements in these experiments.
Notable Assumptions
The argument for the fifth force assumes that the smaller-than-expected measurements are not simply due to experimental error or some other factor. Also, while the stimulus tells us that having a fifth force would resolve these smaller-than-expected measurements, there could be a conflict with other phenomena that might make the fifth force's existence less likely. There could also be ways to explain the unusual measurement based on the original four forces, without needing to come up with a fifth force.
26.
Which one of the following, ██ █████ ████ ███████████ ███ ████████ ████ █████ ██ █ █████ █████████ ██████
a
The extremely sophisticated █████████ ████ ███ ███ ███████████ ███ ███ █████████ ██ ██████████ ██████ ███ ██████
This explains why scientists hadn’t considered the possibility of a fifth force, but it doesn't tell us whether the fifth force actually exists or not. Whether or not scientists were thinking about the fifth force before a certain time period doesn't in itself make the fifth force more or less likely to exist.
Irrelevant corroboration
Irrelevant corroboration
Answers that provide additional support for a claim that the argument doesn't need more support for.
b
No previously established ██████████ ███████ ███ ████████████ ████ ███ ██████ ██ █ █████ █████████ ██████
If this answer choice is true, it strengthens the argument by getting rid of a potential weakness -- that a fifth force might contradict some other aspect of settled science. Since it doesn't contradict other known results, the fifth force seems more likely to exist.
Plausibility
Plausibility
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.
c
Some scientists have █████████ ████ ███ ███████ █████ █████████ █████ ██ ██ ██████ ██ ███████ ██████ ████ █████ ███████████ ██ ███████
This would weaken the hypothesis by suggesting that the fifth force isn't its own force at all, just an aspect of another force.
Directionally wrong
Directionally wrong
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).
d
The experiments were █████████ ██ ██████████ ██ ██████ ██████████ ████████ ██ █████ ███████ █████████ ███ █████ ██ ███████ █████ ███ ██ ████████ ████ ███ ██████ ██ ██████████
This would weaken the hypothesis by calling into question the experiments used to hypothesize the fifth force and making those results seem unreliable.
Directionally wrong
Directionally wrong
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).
e
The fifth universal █████ ███ ██████████ ██ █ ████ ██ █████ ████ █████ ████████ ███ ██████████ █████ ██ ███████████ ███████ ████ ██████████
Whether or not other discoveries in physics were happening is irrelevant to whether or not the fifth force actually exists or not. The hypothesis could still be false even if other legitimate theories were being developed at the same time.