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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Hey nightblade354

Please reformat the stimulus.Sorry to bug you

Thanks!
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Project CR Butler - 2 CR's everyday

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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