Q19 - Paleontologist: It is widely, but falsely

[sumukh09]

Here we have a strengthen EXCEPT question in which we're required to find an answer choice that doesn't add any support to the argument's reasoning.

A paleontologist makes the claim that it is widely and falsely held that life did not exist on land until half a billion years ago. The evidence he uses to draw his conclusion is that traces of carbon-14 have been found through certain 1.2 billion year old rock and this indicates that plants and microbes existed on land at least 1.2 billion years ago.

Answer choices:

A) this is consistent with the stimulus and so it strengthens the argument - the fossils of plants being referred to in this a/c could be those of the ones mentioned in the stimulus and also could be 1.2 billion years old (more than half a billion)

B) Makes it more likely that life existed on land instead of the oceans

C) gives us a reason to believe the evidence in the argument and so is also supporting the conclusion

D) is the correct answer because it weakens the conclusion of the argument; if the Carbon 14 was from soil and not plants then this questions the conclusion that life began on land more than half a billion years ago. We need the carbon 14 to be from plants and microbes but this answer choice says they were formed from soil.

E) This further substantiates the evidence and so supports the argument

[ohthatpatrick]

Nice recap!

Let me just add a couple thoughts on this

(A) is not only compatible with the argument, it actually strengthens the conclusion. If there are fossils from plants that lived on land more than .5 billion years ago, that strengthens the conclusion life on land began more than half a billion years ago.

(C) is really anticipating a potential objection. The premise is that we found carbon 14 (which is associated with life forms) on rocks in North America. Well, the author is assuming that the rocks we find carbon 14 on were "on land" 1.2-billion years ago, not in the ocean.

Just because the rocks are currently on land doesn't mean that they were on land 1.2 billion years ago. (C), confusingly, first presents the idea that some of these rocks WEREN'T on land, but ultimately tells us that some of them WERE on land.

(E) is a really lame strengthen idea. It's unusual for LSAT to substantiate something that was presented as fact in the first place, but that's all (E) does. I would have probably been tempted by (E) as an answer, because it so weakly strengthens, if it weren't for the fact that (D) so completely undermines the argument.

Nice work!

[lunazhuyu]

I am little bit confused about C's wording. What does it mean by saying that 'though portions clearly never were'? what portions? seems to me it's somewhat confusing to understand that C actually means some rocks never submerged in water.