PT61.S2.Q14 - geologists recently discovered marks

Mo Zubair

Having a hard time deciphering answer choice D correctness. Particularly, i am not being able to get over my thinking that D assumes that marks were formed at the place where sandstone was formed. I mean, the marks were formed somewhere else and sandstone was moved to where it was find millions of years after the marks were formed let's say by an earthquake or stuff. Isn't it plausible?

Also, why can't some "early life forms" from answer choice C can leave those marks?

https://7sage.com/lsat_explanations/lsat-61-section-2-question-14/

akistotle

@"Mo Zubair" said:
I mean, the marks were formed somewhere else and sandstone was moved to where it was find millions of years after the marks were formed let's say by an earthquake or stuff. Isn't it plausible?

Since I'm not an expert in this field, I guess it is not impossible. But I assume sedimentary rocks cannot travel far from the place they were formed.

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Phenomenon
・In a piece of sandstone, there are marks resemble worm tracks
・The marks were made before the earliest traces of life.
Hypothesis
・The marks are likely not to be the traces of worms. They are probably the traces of geological processes.

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I think the problem with (C) is that it does not tell us how "early" it is. It's vague. I don't know if it is saying that there were life forms that existed before the earliest traces of life. (C) is like saying, "There are som birds in the Jurassic period that are known to have left marks" but the stimulus is explicitly saying that the marks were formed in the precambrian era.