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22 Aug 2018, 09:27
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Difficulty:
65%
(hard)
Question Stats:
60% (02:18) correct
40%
(02:10)
wrong
based on 1848
sessions
History
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Time
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The near-identical oxygen isotope ratios observed in lunar and terrestrial rocks, combined with the water extracted from lunar volcanic glass having an isotopic composition indistinguishable from the water found on Earth, provides evidence for the giant-impact hypothesis, which holds that a large body striking Earth caused material to break off and form the Moon.
A) near-identical oxygen isotope ratios observed in lunar and terrestrial rocks, combined with the water extracted from lunar volcanic glass having an isotopic composition indistinguishable from the
B) near-identical oxygen isotope ratios observed in lunar and terrestrial rocks, combined with the extraction of water from lunar volcanic glass that is indistinguishable from the isotopic composition of
C) oxygen isotope ratios observed to be nearly identical in lunar and terrestrial rocks, combined with the fact that water extracted from lunar volcanic glass has an isotopic composition indistinguishable from the
D) observation, in lunar and terrestrial rocks, of near-identical oxygen isotope ratios, combined with the extraction of water from lunar volcanic glass that is indistinguishable from the isotopic composition of
E) observation, in lunar and terrestrial rocks, of near-identical oxygen isotope ratios, combined with the fact that the isotopic composition of water extracted from lunar volcanic glass is indistinguishable from that of
A) near-identical oxygen isotope ratios observed in lunar and terrestrial rocks, combined with the water extracted from lunar volcanic glass having an isotopic composition indistinguishable from the
B) near-identical oxygen isotope ratios observed in lunar and terrestrial rocks, combined with the extraction of water from lunar volcanic glass that is indistinguishable from the isotopic composition of
C) oxygen isotope ratios observed to be nearly identical in lunar and terrestrial rocks, combined with the fact that water extracted from lunar volcanic glass has an isotopic composition indistinguishable from the
D) observation, in lunar and terrestrial rocks, of near-identical oxygen isotope ratios, combined with the extraction of water from lunar volcanic glass that is indistinguishable from the isotopic composition of
E) observation, in lunar and terrestrial rocks, of near-identical oxygen isotope ratios, combined with the fact that the isotopic composition of water extracted from lunar volcanic glass is indistinguishable from that of
22 Aug 2018, 09:28
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Official Explanation:-
(1) Take a First Glance (5 seconds)
The first two answers start out the same, but answer (C) changes a decent amount and answers (D) and (E) start with completely different words, so keep an eye out for global issues related to Sentence Structure, Meaning, Modifiers, or Parallelism.
(2) Read for Meaning
This sentence is a real challenge. On SC, if you struggle to decipher the overall meaning of the sentence, you may want to guess your favorite letter and move on. It would be easy to spend 3 minutes on this problem and still end up guessing.
Note that SC never requires specific subject knowledge, so if the science-y language is stressing you out, mentally substitute an abbreviation such as i or Iso for all of that isotope stuff.
The sentence is trying to say that there are two pieces of evidence supporting a particular hypothesis:
The ratios, combined with the water, provides evidence for the hypothesis. To find the subject, mentally strip out the modifier combined with the water. The subject, ratios, is plural, but the verb provides is singular, so eliminate answer (A) for faulty Subject-Verb Agreement.
The original sentence has a couple of other errors—you can dig into these, or you can use the subject-verb error to eliminate additional answers and then directly compare whatever answers remain. It turns out that you can eliminate choices (A), (B), and (C) on the subject-verb issue alone!
If you investigate the additional errors, start by understanding the intended meaning of the sentence. The first piece of evidence is the fact that Iso ratios in both lunar (Moon) and terrestrial (Earth) rocks are nearly identical. The second is that water from lunar volcanic glass and water from Earth are nearly indistinguishable in their Iso composition.
The structure of the second piece of evidence is faulty in the original sentence in two ways. First, combined with water makes it sound as though something is physically being combined with that water. Rather, the sentence is trying to indicate that one fact, combined with another fact, provides support for the theory. In addition, the Comparison (Moon water has an Iso composition indistinguishable from water found on Earth) is illogical. The comparison should be between the two compositions: Moon water has an Iso composition indistinguishable from the Iso composition of Earth water.
(3) Find a Starting Point
Start with any difference that seems easiest to you, then move to the next easiest issue, and so on. Stop when you have one answer or you aren’t sure how to address the remaining differences. All errors for each choice are detailed in the next section.
(4) Eliminate (and Repeat)
(A) The plural subject ratios does not match the singular verb provides. Ratios … combined with water makes it seem as if the ratios are being physically combined with the Moon water. In actuality, the sentence is trying to discuss one fact in combination with another fact. In addition, the comparison of the Iso composition of Moon water with Earth water itself (as opposed to the Iso composition of Earth water) is illogical.
(B) The plural subject ratios does not match the singular verb provides. The other two errors for this choice center around the second piece of evidence. The extraction of the Moon water is not the evidence for the theory; rather, the evidence is the fact that, when researchers extracted this water, they discovered that the Iso composition of the Moon water is indistinguishable from the Iso composition of Earth water. This choice also compares the Moon water itself to the Iso composition of the Earth water; the comparison should be the Iso composition of one to the Iso composition of the other.
(C) The plural subject ratios does not match the singular verb provides. The comparison of the Iso composition of Moon water with Earth water (as opposed to the Iso composition of Earth water) is illogical.
(D) This choice is also very tricky. It is acceptable to say that the observation of a particular fact or outcome provides evidence, so the first part of this choice is fine. The extraction of the Moon water, however, is not the actual evidence for the theory; the evidence is the fact that, when researchers extracted this water, they discovered or observed a particular fact: the Iso composition of Moon water is indistinguishable from the Iso composition of Earth water.
(E) CORRECT. The singular subject observation matches the singular verb provides. Note: the fact that is not part of the subject. In order for two separate words to function as a compound subject, you have to connect them with and (for example, the dog and the cat are friends). In addition, the sentence properly compares the Iso composition of Moon water to the Iso composition of Earth water. It is also logical to say that the observation of a certain thing and the fact that a second thing is true can combine to provide evidence for a certain theory.
(1) Take a First Glance (5 seconds)
The first two answers start out the same, but answer (C) changes a decent amount and answers (D) and (E) start with completely different words, so keep an eye out for global issues related to Sentence Structure, Meaning, Modifiers, or Parallelism.
(2) Read for Meaning
This sentence is a real challenge. On SC, if you struggle to decipher the overall meaning of the sentence, you may want to guess your favorite letter and move on. It would be easy to spend 3 minutes on this problem and still end up guessing.
Note that SC never requires specific subject knowledge, so if the science-y language is stressing you out, mentally substitute an abbreviation such as i or Iso for all of that isotope stuff.
The sentence is trying to say that there are two pieces of evidence supporting a particular hypothesis:
The ratios, combined with the water, provides evidence for the hypothesis. To find the subject, mentally strip out the modifier combined with the water. The subject, ratios, is plural, but the verb provides is singular, so eliminate answer (A) for faulty Subject-Verb Agreement.
The original sentence has a couple of other errors—you can dig into these, or you can use the subject-verb error to eliminate additional answers and then directly compare whatever answers remain. It turns out that you can eliminate choices (A), (B), and (C) on the subject-verb issue alone!
If you investigate the additional errors, start by understanding the intended meaning of the sentence. The first piece of evidence is the fact that Iso ratios in both lunar (Moon) and terrestrial (Earth) rocks are nearly identical. The second is that water from lunar volcanic glass and water from Earth are nearly indistinguishable in their Iso composition.
The structure of the second piece of evidence is faulty in the original sentence in two ways. First, combined with water makes it sound as though something is physically being combined with that water. Rather, the sentence is trying to indicate that one fact, combined with another fact, provides support for the theory. In addition, the Comparison (Moon water has an Iso composition indistinguishable from water found on Earth) is illogical. The comparison should be between the two compositions: Moon water has an Iso composition indistinguishable from the Iso composition of Earth water.
(3) Find a Starting Point
Start with any difference that seems easiest to you, then move to the next easiest issue, and so on. Stop when you have one answer or you aren’t sure how to address the remaining differences. All errors for each choice are detailed in the next section.
(4) Eliminate (and Repeat)
(A) The plural subject ratios does not match the singular verb provides. Ratios … combined with water makes it seem as if the ratios are being physically combined with the Moon water. In actuality, the sentence is trying to discuss one fact in combination with another fact. In addition, the comparison of the Iso composition of Moon water with Earth water itself (as opposed to the Iso composition of Earth water) is illogical.
(B) The plural subject ratios does not match the singular verb provides. The other two errors for this choice center around the second piece of evidence. The extraction of the Moon water is not the evidence for the theory; rather, the evidence is the fact that, when researchers extracted this water, they discovered that the Iso composition of the Moon water is indistinguishable from the Iso composition of Earth water. This choice also compares the Moon water itself to the Iso composition of the Earth water; the comparison should be the Iso composition of one to the Iso composition of the other.
(C) The plural subject ratios does not match the singular verb provides. The comparison of the Iso composition of Moon water with Earth water (as opposed to the Iso composition of Earth water) is illogical.
(D) This choice is also very tricky. It is acceptable to say that the observation of a particular fact or outcome provides evidence, so the first part of this choice is fine. The extraction of the Moon water, however, is not the actual evidence for the theory; the evidence is the fact that, when researchers extracted this water, they discovered or observed a particular fact: the Iso composition of Moon water is indistinguishable from the Iso composition of Earth water.
(E) CORRECT. The singular subject observation matches the singular verb provides. Note: the fact that is not part of the subject. In order for two separate words to function as a compound subject, you have to connect them with and (for example, the dog and the cat are friends). In addition, the sentence properly compares the Iso composition of Moon water to the Iso composition of Earth water. It is also logical to say that the observation of a certain thing and the fact that a second thing is true can combine to provide evidence for a certain theory.
General Discussion
