Critical Reasoning

Some scientists believe that 65 million years ago an asteroid struck what is now the Yucatan Peninsula, thereby causing extinction of the dinosaurs. These scientists have established that such a strike could have hurled enough debris into the atmosphere to block sunlight and cool the atmosphere. Without adequate sunlight, food sources for herbivorous dinosaurs would have disappeared, and no dinosaurs could have survived a prolonged period of low temperatures. These same scientists, however, have also established that most debris launched by the asteroid would have settled to the ground within six months, too soon for the plants to disappear or the dinosaurs to freeze.
Which one of the following, if true, most helps to resolve the apparent discrepancy between the scientists' beliefs and the scientists' results, as described above?
(A) Loss of the herbivorous dinosaurs would have deprived the carnivorous dinosaurs of their food source.
(B) Dinosaurs inhabited most landmasses on the planet but were not especially abundant in the area of the asteroid strike.
(C) A cloud of debris capable of diminishing sunlight by 20 percent would have cooled the earth's surface by 7 to 10 degrees Celsius.
(D) The asteroid was at least 9.6 km in diameter, large enough for many dinosaurs to be killed by the strike itself and by subsequent tidal waves.
(E) Dinosaurs were susceptible to fatal respiratory problems cause by contamination of the air by asteroid debris.

(A) Loss of the herbivorous dinosaurs would have deprived the carnivorous dinosaurs of their food source.
Incorrect : This makes the assumption that herbivorous dinos are extinct. But in the stimulus it is stated that debris settled before plants died. Hence we cannot conclude that herbivorous dinos became extinct.

(B) Dinosaurs inhabited most landmasses on the planet but were not especially abundant in the area of the asteroid strike.
Incorrect : This is clearly out of scope

(C) A cloud of debris capable of diminishing sunlight by 20 percent would have cooled the earth's surface by 7 to 10 degrees Celsius.
Incorrect : Irrelevant

(D) The asteroid was at least 9.6 km in diameter, large enough for many dinosaurs to be killed by the strike itself and by subsequent tidal waves.
Incorrect : The death of many dinosaurs is NOT equal to the extinction of dinosaurs.

(E) Dinosaurs were susceptible to fatal respiratory problems cause by contamination of the air by asteroid debris.
Correct : This sentence explains why dinosaurs died from the impact even though the plants did not die and it wasn't cold enough for them to freeze to death. Therefore it solves the paradox.
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My pick is (E)

IMO E
A) Loss of the herbivorous dinosaurs would have deprived the carnivorous dinosaurs of their food source.
We are talking here about fast cause of extinction. I believe there must be a longer period of time (>6months) in order all carnivorous dinos to kill herbivorous ones.

(B) Dinosaurs inhabited most landmasses on the planet but were not especially abundant in the area of the asteroid strike.completely irrelevant.

(C) A cloud of debris capable of diminishing sunlight by 20 percent would have cooled the earth's surface by 7 to 10 degrees Celsius.this choice states concrete facts about the freezing processes. we do not need that.

(D) The asteroid was at least 9.6 km in diameter, large enough for many dinosaurs to be killed by the strike itself and by subsequent tidal waves.ok, it presents an evidence about the size of the asteroid and its consequences. In the argument there is an information about debris and/or freezing, not tidal waves or the size of an asteroid. In addition, it is stated that 6 months is a short period for plants to disappear. If there were waves - where were the plants then?

(E) Dinosaurs were susceptible to fatal respiratory problems cause by contamination of the air by asteroid debris. best choice. in the scope of the argument and provides an alternative

Some scientists believe that 65 million years ago an asteroid struck what is now the Yucatan Peninsula, thereby causing extinction of the dinosaurs. These scientists have established that such a strike could have hurled enough debris into the atmosphere to block sunlight and cool the atmosphere. Without adequate sunlight, food sources for herbivorous dinosaurs would have disappeared, and no dinosaurs could have survived a prolonged period of low temperatures. These same scientists, however, have also established that most debris launched by the asteroid would have settled to the ground within six months, too soon for the plants to disappear or the dinosaurs to freeze.
Which one of the following, if true, most helps to resolve the apparent discrepancy between the scientists' beliefs and the scientists' results, as described above?
(A) Loss of the herbivorous dinosaurs would have deprived the carnivorous dinosaurs of their food source.
(B) Dinosaurs inhabited most landmasses on the planet but were not especially abundant in the area of the asteroid strike.
(C) A cloud of debris capable of diminishing sunlight by 20 percent would have cooled the earth's surface by 7 to 10 degrees Celsius.
(D) The asteroid was at least 9.6 km in diameter, large enough for many dinosaurs to be killed by the strike itself and by subsequent tidal waves.
(E) Dinosaurs were susceptible to fatal respiratory problems cause by contamination of the air by asteroid debris.


Read the question carefully: It gives us a hint if already not understood that there is a discrepancy between the scientists belief and scientists results.

Conclusion: Scientists believe that extinction of dinosaurs was due to the asteroid strike

Premise: 1. Scientists have established that debris could have blocked sunlight and cooled the atmosphere. Herbi have died of lack of plants and both carni and herbi could have died of low temperatures.

Premise:2 Same scientists have also established that debris could not take more than 6 months to settle and is a less time for plants to vanish and dinosaurs to freeze.

Hence from premises, it is finally concluded that "Debris due to asteroid strike" cannot probably be the reason of extinction
However, conclusion is that asteroid strike was the reason of conclusion.

Discrepancy does not mean that the conclusion is wrong. It just means that there is something more than meets the eye. One thing to clearly remember that NEITHER Premise, nor conclusion is wrong in Discrepancy. However, premise can never be wrong and conclusion can be weak . So we need to take into consideration a question before approaching discrepancy answer choices:

"Why is it that the asteroid strike lead to dinosaur extinction, although debris could not cause loss of plants and freezing of dinousars?


This tells us that we must find some reason to think of debris being the reason of extinction of dinosaurs. This kind of prephrasing is enuf for Paradoz questions.

PoE:

A) Loss of the herbivorous dinosaurs would have deprived the carnivorous dinosaurs of their food source.

First of all Premise itself says that plants wont be lost due to lack of sunlight as the debris thus raised by this asteroid strike would have settled down within 6 months, time less for plants to die. So no point of loss of Herbivores. Does it answer the question above. No. Go ahead.

(B) Dinosaurs inhabited most landmasses on the planet but were not especially abundant in the area of the asteroid strike

Asteroid strike lead to extinction of dinosaurs. This is a part of conclusion. Dont deny conclusion in Paradox. Take it as true and find alternate reasons to plug in the discrepancy.


(C) A cloud of debris capable of diminishing sunlight by 20 percent would have cooled the earth’s surface by 7 to 10 degrees Celsius

Does this extra information solve our discrepancy? If you have forgotten discrepany by this time, look at the question. Does this answer solve the question? There is no information in terms of numbers presented in the argument and hence we cannot solve this discrepancy by providing any numbers or percents.

(D) The asteroid was at least 9.6 km in diameter, large enough for many dinosaurs to be killed by the strike itself and by subsequent tidal waves.

Does debris come into picture here? See, we need to resolve discrepancy between extinction (belief) and debris (the result). We need alternate cause for debris causing extinction and not alternate cause for extinction. This is a typical Shell Game Answer (Powerscore Bible Fans must know)

(E) Dinosaurs were susceptible to fatal respiratory problems cause by contamination of the air by asteroid debris.

Does it Answer? Yes it does.


This is a very good question to help sharpen paradox skills.

I believe the answer should be A