<p>I answered 2 CR questions incorrectly on the PSATs, and one of them was a science related passage. This is the usual pattern. For those of you who got this question right on the PSATs or could help me, what is your thought process when going through the answers for question 11, section 1?</p>
<p>Here is the passage:
One model of lunar origin had the Moon forming at the same time and place as Earth, by condensing from an enormous disk of gas and dust surrounding the early Sun. But the Moon’s density is little more than half that of Earth. The difference in density had led some to propose that the Moon lacks an iron core like the one in Earth’s innards, and indeed, seismic readings from the moon confirmed that the lunar core is mall to nonexistent. If the moon was born at the same time and in the same region of the solar system as Earth, why doesn’t it have a core like that of Earth?</p>
<p>The main purpose of the passage is to:
(a) challenge the reliability of an observation
(b) shake the foundations of a science
(c) indicate the weakness of a theory
(d) question the validity of an experiment
(e) expose the implausability of a prediction</p>
<p>Choice A - The passage does not challenge the observations of the different cores of the moon and the earth. Rather, it takes these observations to question the theory that says the “moon was born at the same time and in the same region of the solar system.”</p>
<p>Choice B is too extreme.</p>
<p>Choice D - Nowhere does the passage question the validity of an experiment. Again, it uses the information recorded from the experiment to challenge a theory.</p>
<p>Choice E is illogical - there is no prediction mentioned in the passage. It is a theory that the moon was born at the same time as the earth in the same region of the solar system, not a prediction.</p>
<p>A - the poster above gives a good explanation to why its wrong. He is not challenging the reliabillity of it.</p>
<p>B - No where does it say its going to transform science radically. Radical answers are almost always wrong.</p>
<p>C - Yup this is the answer. Pay attention to the first, second and last sentences of the passage. They give it away. The first and second sentence say that the Eearth and moon is thought to have been formed at the same time but they have different sized cores. Then the last sentence says if this theory is true, why doesnt the moon have a core of the same size of the Earth? He is putting that question out there for the reader to pretty say that there is a weakness in the theory.</p>
<p>D - No experiments were conducted</p>
<p>E - There were no predictions, just a theory.</p>
<p>^Yeah it’s C. I think the key distinction between C and D is theory vs. experiment. The idea that the moon originated from gasses surrounding the sun was a theory, not an experiment.</p>
<p>The first sentence provides the theory —> “One model of lunar origin had…”. The reason I think this is not an experiment is that the passage simply never provides any evidence of any sort of experiment. So I would use the first sentence to assume this to be a theory.</p>
<p>The whole paragraph serves to challenge it, but it’s the last sentence that makes this challenge the most clear —> “If the moon was born at the same time and in the same region of the solar system as Earth, why doesn’t it have a core like that of Earth?”</p>
<p>The “If so, then why” statement is clearly a challenge. So I would go with C.</p>