Q19 - Researchers working in Western

[atzhang6v6]

I was not sure between A and C.
I thought C might be correct because it says "These microscopic crystals measure only 50 microns across and were formed 4.2 billion years ago" and "...how long it took for the Earth's crust to form, since this date is only 300 million years after the formation of the Earth itself" so I thought maybe it took about 4 billion years...

[ManhattanPrepLSAT1]

Hey atzhang6v6, not quite

I thought C might be correct because it says "These microscopic crystals measure only 50 microns across and were formed 4.2 billion years ago" and "...how long it took for the Earth's crust to form, since this date is only 300 million years after the formation of the Earth itself" so I thought maybe it took about 4 billion years...

Both (A) and (C) set time frames for the creation of the Earth's crust. (A) says that it took no longer than 300 million years to begin to form, while (C) says it took billions of years to form (finish).

The microdiamonds are evidence of when it began to form, answer choice (A), not when it finished forming, answer choice (C).

Incorrect Answers
(B) is too strong. We know the Earth's crust formed there, but not that it formed there first.
(C) is too strong. We could say it took at least 300 million years to form, but not billions of years.
(D) is too strong. We know that microdiamonds are components of the Earth's crust, but not that they were the first component.
(E) is too strong. We know that some microdiamonds formed at the time the Earth's crust was forming, but not that all of them did.

[jm.kahn]

(E) is too strong. We know that some microdiamonds formed at the time the Earth's crust was forming, but not that all of them did.

I initially thought E was a very strong choice and is hard to eliminate. I read matt sherman's explanation for E but I don't think it's correct. The reason being the way microdiamonds are defined in the stim -- "oldest fragments of the earth's early crust that have yet been identified: microdiamonds"

The usage of colon means that the phrase preceding it defines what microdiamonds are. That is, microdiamonds are oldest fragments of the earth's early crust that have yet been identified. This means ANY and "ALL" microdiamonds are defined as such.
Does any one notice this grammar issue?

[SameerS691]

(E) is too strong. We know that some microdiamonds formed at the time the Earth's crust was forming, but not that all of them did.

I initially thought E was a very strong choice and is hard to eliminate. I read matt sherman's explanation for E but I don't think it's correct. The reason being the way microdiamonds are defined in the stim -- "oldest fragments of the earth's early crust that have yet been identified: microdiamonds"

The usage of colon means that the phrase preceding it defines what microdiamonds are. That is, microdiamonds are oldest fragments of the earth's early crust that have yet been identified. This means ANY and "ALL" microdiamonds are defined as such.
Does any one notice this grammar issue?

I agree and had the same issue. I chose E as I had misread and not noticed the "to start to form" in A. I can see why A is a better answer as it makes an assumption that can be more clearly supported by the stimulus. But I still believe there is an issue with how they defined microdiamonds in the stimulus, and it doesn't indicate that microdiamonds could have occurred in the future. Are we expected to infer this from geological knowledge/common sense?

[ZaftigG65]

The usage of colon means that the phrase preceding it defines what microdiamonds are. That is, microdiamonds are oldest fragments of the earth's early crust that have yet been identified. This means ANY and "ALL" microdiamonds are defined as such.
Does any one notice this grammar issue?

Consider the following sentence. "I've just discovered a moldy mass in my fridge; cheese." Does this mean that ANY and ALL cheeses are defined as such; a moldy mass in my fridge?