Scientists formerly believed that the rocky planetsEarth, Mercury,

Question

Scientists formerly believed that the rocky planets—Earth, Mercury, Venus, and Mars—were created by the rapid gravitational collapse of a dust cloud, a deﬂation giving rise to a dense observation. That view was challenged in the 1960s when studies of Moon craters revealed that these craters were caused by the impact of objects that were in great abundance about 4.5 billion years ago but whose number appeared to have quickly decreased shortly thereafter. This  observation  rejuvenated Otto Schmidt’s 1944 theory of accretion. According to this theory, cosmic dust gradually lumped into ever-larger conglomerates: particulates, gravel, small and then larger balls, planetesimals (tiny planets), and, ultimately, planets. As the planetesimals became larger, their numbers decreased. Consequently, the number of collisions between planetesimals decreased.    1 
 1. The passage provides evidence that Schmidt would be likely to disagree with the theory presented in the frst sentence over

I. the length of time it took for the rocky planets to form.
II. the most likely causes of the Moon’s impact craters.
III. the importance of cosmic dust as a seminal material in planetary formation.

A. I only
B. III only
C. I and II only
D. I and III only
E. II and III only

2 
 2. Which of the following best describes the “observation” (line 6) referred to in the passage?

A. The rocky planets were created by the rapid gravitational collapse of a dust cloud.
B. Certain features on the Moon’s surface are impact craters caused by collisions with objects such as planetesimals.
C. The rocky planets were formed by a slow accretion of cosmic dust into increasingly larger bodies.
D. The number of objects colliding with the Moon appears to have been high for a while and then rapidly diminished.
E. Tere are far fewer planetesimals in existence today than there were about 4.5 billion years ago.

RC Butler 2022  -  Practice Two RC Passages Everyday.   
Passage # 284 Date: 15-Jul-2022
 This question is a part of RC Butler 2022 .  Click here for Details

Naman1313 · Answer

Acc to me, 
ques 1 - ans E 
ques 2 - ans B

correct me if i'm wrong.

sunitapandey · Answer

1. The passage provides evidence that Schmidt would be likely to disagree with the theory presented in the first sentence over

I. the length of time it took for the rocky planets to form.
II. the most likely causes of the Moon’s impact craters.
III. the importance of cosmic dust as a seminal material in planetary formation.

B. III only-- Correct, As per the first sentence the rocky planets were formed by collapsing of dust cloud. But later Schmidt states that it is because of the formation of dust lumps. So his argument was around cosmic dust.

sunitapandey · Answer

2. Which of the following best describes the “observation” (line 6) referred to in the passage?

A. The rocky planets were created by the rapid gravitational collapse of a dust cloud.
 B. Certain features on the Moon’s surface are impact craters caused by collisions with objects such as planetesimals.- Correct  
C. The rocky planets were formed by a slow accretion of cosmic dust into increasingly larger bodies.
D. The number of objects colliding with the Moon appears to have been high for a while and then rapidly diminished.
E. Tere are far fewer planetesimals in existence today than there were about 4.5 billion years ago.

RanonBanerjee · Answer

1. Option A.

Explanation: First sentence says- Scientists formerly believed that the rocky planets—Earth, Mercury, Venus, and Mars—were created by the  rapid  gravitational collapse of a dust cloud, a deﬂation giving rise to a dense orb. so it indicates a fast process. 
On the other hand Schimdt's theory says, 
"Schmidt’s 1944 theory of accretion. According to this theory, cosmic dust  gradually  lumped into" so its a slow process.

Stem II is wrong, because the first theory does not provide any explanation to what caused the craters while Schimdt's theory does. No ground of disagreement whatsoever.

Stem III is wrong because, both theories mention cosmic dusts and dust clouds , but none of them particularly recognizes it in any way. All they care about is  How  the planets are formed, not  what  constitute those.

2. Option D.

We need to rephrase the bold part in the given sentence: That view was challenged in the 1960s when studies of Moon craters revealed that these  craters were caused by the impact of objects that were in great abundance about 4.5 billion years ago but whose number appeared to have quickly decreased shortly thereafter.

YB114 · Answer

Sajjad1994  , In 2nd question , Option B is very well inferred from the passage that "Certain features on the Moon’s surface are impact craters caused by collisions with objects such as planetesimals" and Option D : Told about the collision by objects as well as the object where available before and then diminished.

so in such type of question where you we need to best describe the role of a particular word , here it is "observation" , here we always need to select answer choice which is word to word match with the passage (like in option D) ? and please provide a reason for elimination of choice B.

Sajjad1994 · Answer

Option B  is incorrect because it specifically refers to features on the Moon's surface being impact craters caused by collisions with objects such as planetesimals. While it is true that the passage mentions Moon craters being caused by the impact of objects, the observation discussed in the passage is not limited to the Moon's surface features. The broader observation is about the general decrease in the number of objects colliding with the Moon over time, and this observation led to a reevaluation of the formation of rocky planets.

Sajjad1994 · Answer

You are right! Fixed now.

mollyweasley · Answer

My issue with Choice D of question 2 is that it says "been high  for a while  and then rapidly diminished". But the passage says that "objects were in great abundance 4.5 billion years ago but whose numbers appeared to have quickly diminished  shortly thereafter ". The contrast between "for a while" and "shortly thereafter" led me to pass on this option.  GMATNinja   Bunuel   KarishmaB  any thoughts on this?

Scientists formerly believed that the rocky planetsEarth, Mercury,

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Scientists formerly believed that the rocky planetsEarth, Mercury,

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