Scientists examined diamonds that were formed on Earth about 2.9

Question

Scientists examined diamonds that were formed on Earth about 2.9 billion years ago. These diamonds had a higher-than-normal concentration of sulfur-33. This
concentration can be explained only by certain chemical reactions that are stimulated by ultraviolet light. If there had been more than a trace of oxygen in Earth's
atmosphere 2.9 billion years ago, then not enough ultraviolet light would have reached Earth 's surface to stimulate the chemical reactions.

The information above most strongly supports which one of the following?

The information above most strongly supports which one of the following?

(A) Most diamonds with higher-than-normal concentrations of sulfur-33 were formed at least 2.9 billion years ago.
(B) Ultraviolet light causes the oxygen in Earth's atmosphere to react chemically with sulfur-33.
(C) Earth's atmosphere contained very little, if any, oxygen 2.9 billion years ago.
(D) Sulfur-33 is rarely found in diamonds that were formed more recently than 2.9 billion years ago.
(E) The formation of diamonds occurs only in the presence of ultraviolet light.

Source: LSAT

elavendan1 · Answer

C- Argument says that if there is any oxygen, then UV light would not have passed through atmosphere. So, it is obvious that there is no/little amount of oxygen present to allow uV light to stimulate chemical reaction.

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AkshdeepS · Answer

1. Oxygen does not allow the UV rays to reach earth.
2. More UV rays, more stimulation and more sulfur-33.
3. So if more sulfur - 33 found in diamonds 2.9 billions years ago, this means more UV rays were reaching earth's surface.

This implies that less oxygen was present at that time. (C) is the correct answer.

(A)  Most diamonds with higher-than-normal concentrations  of sulfur-33 were formed at least 2.9 billion years ago.

(B)  Ultraviolet light causes the oxygen  in Earth's atmosphere to react chemically with sulfur-33.

(C) Earth's atmosphere contained very little, if any, oxygen 2.9 billion years ago.

(D) Sulfur-33 is rarely found in diamonds that were  formed more recently than  2.9 billion years ago.

(E) The formation of diamonds occurs  only in the presence of ultraviolet light.

gmat1393 · Answer

Hey  nightblade354

Please reformat the stimulus.Sorry to bug you

Thanks!

nightblade354 · Answer

Fixed.

-- Mod Nightblade

rever08 · Answer

This stimulus presents a set of facts about research into the sulfur content of diamonds formed on Earth about 2.9 billion years ago. It turns out that the diamonds had a higher-than-normal concentration of sulfur-33.

First, only certain chemical reactions, stimulated by ultraviolet light, can account for the higher-than-normal concentration of sulfur-33 found in the diamonds. This is a conditional relationship.

Sufficient =>Necessary

Next, we are given another conditional relationship: “if there had been more than a trace of oxygen in Earth’s atmosphere 2.9 billion years ago, then not enough ultraviolet light would have reached Earth’s surface to stimulate the chemical reactions.”

Pre-thinking: 
This chain provides the additive inference that if diamonds have a higher-than-normal concentration of sulfur-33, then it must be the case that there was not more than a trace of oxygen in Earth’s atmosphere 2.9 billion years ago:

Choice (A): The stimulus discussed only the chemical composition of certain diamonds, which were known to have been formed about 2.9 billion years ago. 
This answer choice goes beyond that evidence by making an inference about most diamonds with higher-than-normal concentrations of sulfur-33.

Choice (B): It contains several relevant pieces of information but is incorrect since it places those pieces into unsupported relationships.

Choice (C): This is the correct answer choice. Reflects the additive inference described above.

Choice (D): The stimulus did not tell us anything about the chemical composition of diamonds formed more recently than 2.9 billion years ago, so this statement is out of scope.

Choice (E): This answer choice mistakes the role played in the stimulus by ultraviolet light, which stimulated chemical reactions necessary for the higher-than-normal concentrations of sulfur-33 in the diamonds. The stimulus did not state that the presence of ultraviolet light was necessary for the formation of diamonds generally.

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zac123 · Answer

C is the answer as it can be properly inferred from the argument .

VerbalBot · Answer

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Scientists examined diamonds that were formed on Earth about 2.9

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Scientists examined diamonds that were formed on Earth about 2.9

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