Q15

[lhermary]

Wow! What a hard passage. I understand why B is right here but why is C wrong?

Thanks

[ManhattanPrepLSAT1]

You are absolutely right, this is a hard passage!

The main point needs to encompass the purpose in writing this passage, which is to describe what NGF is and state the significance of it's discovery - best expressed in answer choice (B).

Lets look at each of the incorrect answers:

(A) is too specific to chick embryos.
(C) is too focussed on NGF. While this is the topic of the entire 2nd paragraph, it's not broad enough and should have included the point that NGF was just the first neurotropic factor discovered that paved the way to understanding how this class of cell-growth factors impacts cell development and survival.
(D) doesn't give Levi-Montalcini enough credit. She was more than "partly" responsible. Additionally, I'm not sure about the claim that neurotropic factors are produced only by tissues to which nerves are already connected.
(E) is too specific about what NGF does and does not reflect on the significance of the discovery.

Let me know if you have further questions on this one!

[stjohnmccloskey]

When I read the passage, it reads as an informative passage about some sciency stuff
there's only one sentence that mentions importance.
Is that enough? it just seems too...little! there doesn't seem to be enough there, the whole rest of the passage is purely informative about the experiment, and the findings. Is that one sentence enough to say that it's the "main point?"
It seems to me that it's not the main point, because the passage doesn't support how important the discovery was, it only describes what the particular discovery was and how it came about?

[ManhattanPrepLSAT1]

Good question, and your issue with answer choice (B) is a familiar one to RC in general. However, even if the location of the author's tone of voice indicating approval, disapproval, or ambivalence to a view/finding is brief that does not change the fact that the author does hold an opinion regarding the matter and will be reflected in the correct answer to the "Main Point" question.

The author indicates in line 8 that Levi-Montalcini's discovery was "crucial" and correlates nicely with the language "pivotal development" from answer choice (B).

Hope that helps!

[deedubbew]

I've heard the rule from a handful of instructors here that when answering global questions, you should choose the answer choice according to how much of the passage is covered. Answer choice C points to the tissue experiments which is the largest paragraph in the passage. B makes not mention of it.

[tommywallach]

Yeah, that's a good general rule. Not 100% foolproof, but close.

[JinZ551]

To me, answer C is not correct also because no where in the passage suggests the new tissue technique is devised by Rita

any thought?

[MoiseiD954]

I agree with JinZ551.

C) also felt contradicted to me because only one of the two experiments "used the technique of tissue culture"; however, answer choice C says "a series of
experiments" used this technique.

Any thoughts/comments from LSAT Geeks would be appreciated.

[IrisH894]

2 things wrong with C:
1. tissue culture wasn't used in a series of experiments, it was used in one experiment.
2. NGF is not necessary for the survival and functioning of nerve cells. NGF can serve this role, but it's not the only cell-growth factor out there. Other neurotrophic factors can presumably help t nerve cells survive and thrive even when NGF is absent.

I actually don't agree with the above poster on C being wrong because it only focuses on NGF and therefore is too narrow. This passage only talks about on NGF, from the experiments and research that led to its discovery (paragraph 2) and the fuction it serves in nerve cell development (paragraph 3). Notice that the anthor never really talked about other growth factors nor extend the conclusion to include those factors.

C is not the right answer because it's inaccurate, not because it's incomplete.