Key Steps
- Read the question (do this for every question!)
- Read the passage
- In your own words, make a conclusion for the passage. What is the author’s main idea?
- Find a sentence in the text that matches the conclusion you made, and underline it.
- Keep an eye out for giveaway words and phrases
- Find an answer that matches the underlined sentence.
In this passage, the author talks about the deviations in the orbits of Uranus and Neptune. Since the data is so old and potentially inaccurate, we cannot know if there is another planet or not. The conclusion of the text will be related to what we can conclude based off the causes for the deviations in orbits - what is the outcome of these deviations?
A The use of old and inaccurate data indicates that Planet X cannot exist:
This is not true because there is still the possibility that planet X exists. Although this planet is not guaranteed to be the cause of these deviations, it could be. Notice the language ‘… Uranus and Neptune will deviate from them even if there is no Planet X’. ‘Even if’ suggests that there is still a chance of there being a Planet X although not required to cause these deviations. Therefore A is incorrect.
B Astronomers are right to think that there must be an undiscovered planet:
The text is proving that, contrary to some astronomers’ beliefs, there is not necessarily the need to have an undiscovered planet. The author bases this on the old data used to calculate the orbits of the planets, so it would not be 100% right for the astronomers to believe every calculation would be accurate. This means that their expected deviations due to another planet (X) being present could be caused by anything else, giving reasons for them to be more sceptical about the actual cause of deviations. Therefore B is incorrect.
C The deviations in the orbits of Uranus and Neptune cannot tell us whether Planet X exists:
The text argues that the deviations will be present regardless or not if Planet X is present. Therefore if we had to make a conclusion on the deviations of orbits of Uranus and Neptune, we could only say that they do not tell us whether or not there is a Planet X because the data is outdated and the orbits calculated could be wrong. This explains why C is correct.
D The calculations of the orbits of Uranus and Neptune are probably wrong:
Although this is a true statement, it is missing that extra statement. What can we say now that we know the calculations are probably wrong? What does this cause? This would be the final conclusion. So D is incorrect because it is missing that final result based off what happens since the calculations are probably wrong.
E Uranus and Neptune will deviate from the predicted orbits whether or not Planet X exists:
This is a tricky option and easily confusable with C, but the difference here wording. In C, we say something conclusive because the fact that there could be deviations in the orbit due to inaccurate data leads to the conclusion that these deviations cannot tell us if there is a Planet X because we do not know what the deviations are. In E, it is saying certainly that the planets will deviate from their predicted orbits. This is not true, we know that there is a high chance of these planets deviating but the wording is all hypothetical: “likely”, “probably”. Therefore E is incorrect because it confuses something with a high chance of happening with something that is certain.