#23 - Each of many different human hormones can by itself

[Administrator]

Complete Question Explanation

Main Point. The correct answer choice is (B)

This Main Point question is considered to be very difficult by most test takers because it features
multiple conclusions – a main conclusion and a subsidiary conclusion. Since the test makers are aware
that test takers use common indicators to identify conclusions, many subsidiary conclusions are prefaced
by words like “thus” or “therefore.” Also, the test makers often seek to draw attention away from the
main conclusion by deliberately placing the subsidiary conclusion at the end of the stimulus.

For this stimulus, the first sentence is clearly a premise. The second statement is a conclusion which
explains the first observation. The third statement begins with the words, “To see this,” indicating
that this portion of the argument will provide additional clarification of the conclusion that was just
presented. The final sentence is a secondary (or subsidiary) conclusion, indicated by the word “thus.”
This conclusion is based on the previous sentence and explains the consequence of low blood glucose
levels.

To correctly identify the main conclusion, consider the primary purpose of the argument. Is the argument
primarily structured to prove that low blood glucose levels can lead to unconsciousness and death? If so,
would the stimulus need to mention that several hormones can independently raise blood glucose levels?
This premise would be superfluous if the stimulus was primarily intended to demonstrate the effects of
low blood glucose levels. Do not be fooled by the conclusion indicator and order of presentation – the
main conclusion of this stimulus is the second sentence.

As proof of this interpretation, test takers may wish to recompose the stimulus. Here is a possible
paraphrase of the stimulus which emphasizes the correct conclusion: “Since brain cells can only
use glucose to produce energy, low blood glucose levels can lead to unconsciousness or death. This
metabolic quirk of the brain is probably the reason why each of many different human hormones can by
itself raise the concentration of glucose in the blood.”

Answer choice (A): As previously discussed, answer choice (A) is a premise of the stimulus given in
support of the second sentence.

Answer choice (B): This is the correct answer choice. Each of the other statements in the stimulus
is intended to support this conclusion. Note that the pronoun “this” in the second sentence has been
replaced here with its antecedent (the information in the first sentence).

Answer choice (C): Like answer choice (A), this is another premise in the stimulus (the third sentence).
It leads to the subsidiary conclusion.

Answer choice (D): This secondary conclusion is based on the evidence provided in answer choice (C).
Based on this conclusion, the evolutionary advantage of having several different ways to raise blood
glucose levels becomes clear.

Answer choice (E): Do not eliminate this answer choice simply because it does not appear in the
stimulus. Some questions require test takers to provide a conclusion that is not explicitly contained
within the stimulus. This answer choice closely resembles the correct answer choice in form. However,
the content of this answer is incomplete. Rather than explaining the entire argument, this statement only
refers to the relationship between the second premise and the subsidiary conclusion (the third and fourth
sentences).

[cecilia]

The human hormones question in the 3rd LR section of the June 04 exam:

I struggled between the 2nd and 4th sentence in the stimulus over which was the conclusion. In addition, the 4th sentence starting with a traditional conclusion indicator ("thus") didn't really help things out either. Does this happen often, where LSAT people will deliberately use a conclusion indicator to confuse us? OTher than the "therefore test" is there another way to nail down the conclusion? Thanks in advance.....

[Steve Stein]

Thanks for your question--that's a tough one, because it has both a main conclusion and a subsidiary conclusion. I think the conclusion indicator is indeed there deliberately, to catch test takers who rely too much on indicators. It's great that you struggled between the two conclusions--when you encounter such a situation, ask yourself which is being proven and which is doing the proving:

Premise: The brain can only use glucose.
Sub-conclusion: Thus, if blood glucose drops too low, the brain will starve and die.
Main Conclusion: (Therefore) this strange quirk of the brain is probably the reason that a lot of different hormones can raise glucose levels.

Good question! I hope that's helpful--please let me know--thanks!

~Steve

[cecilia]

Thanks Steve! Very helpful explanation.

[jonwg5121]

I've noticed that I have been having trouble identifying the main conclusion whenever main point question stems come up. It has been very frustrating. I am unable to determine sometimes whether a statement is a premise, subsidiary conclusion, or main conclusion although I am familiar with their definitions (I have trouble figuring out which is being proven and which is doing the proving)

For example, on June 2004 Section 3 LR #23, I ended up choosing (A) as the main conclusion. However, I couldn't tell if this was a premise or conclusion. The only statements I were certain of were

Premise: "To see this, consider that although most human cells can produce energy from fats and proteins, brain cells can use only glucose"

Subsidiary Conclusion: Thus, if blood glucose levels fall too law, brain cells will rapidly starve, leading to unconsciousness and death"

The other two, I was unsure. If you can please walk me through this problem, how to approach it systematically, and what your thought processes are, it would be extremely helpful. Also, if there are any extra practice problems you can refer me to, that would be appreciated. Thanks!

[jeff.wren]

Hi Jon,

This question is a tricky one.

In this argument, the first sentence states a factual observation, and the second sentence is a conclusion that provides an explanation for this observation. The third sentence begins "To see this" which provides clarification for the conclusion in the second sentence. The final sentence is a subsidiary conclusion that is used to support the main conclusion.

One thing that can be helpful is to try rearranging the sentences to better see how the argument is built and how the logic flows. If you find two conclusions in an argument, one trick is to read them back-to-back and then reverse the order to see which sounds better. The main conclusion should follow from the subsidiary conclusion and should sound correct. The other way should sound backwards.

Another thing to remember is that the main conclusion is unlikely to be in the last sentence in a main point question, as this is where people expect it to be. Don't be fooled by the word "thus" in the last sentence. The testmakers are hoping that people will assume that the last sentence is the main conclusion.

These tips also can be helpful for Method of Reasoning-Argument Part questions, which are covered in lesson 7.

I hope this helps answer your question.

Best,
Jeff

[jonwg5121]

Thank you. Just to make sure I get it a factual observation is not necessarily a premise, or is it? And when you mean "The main conclusion should follow from the subsidiary conclusion and should sound correct. The other way should sound backwards."

Sounds Correct then
Subsidiary Conclusion
to
Main Conclusion

Sounds Incorrect then
Main Conclusion
to
Subsidiary Conclusion

Thanks!

[Dave Killoran]

Hi Jon,

Thanks for the questions! These are all key ideas, so you are definitely on the right path in wanting to make sure you get this all straight.

Factual statements are premises (unless there is no conclusion present, in which case they are just part of a fact set).

As far as subsidiary conclusions and main conclusions, you are correct. A subsidiary conclusion is "underneath" or supports the main conclusion. In this sense, it is a conclusion that follows form a premise, but it is then also used as a premise itself to support the main conclusion. So, when you have a subsidiary conclusion, the main conclusion will follow from it, and "sound" correct. If you have it incorrectly aligned (main conclusion followed by subsidiary), then it won't "sound" right.

Please let me know if that helps. Thanks!

[Nfontes93]

I am stuck between answer choices B and D. Can someone explain to me the purpose of D in the stimulus?

[Dave Killoran]

Hi N,

That last sentence is a sub-conclusion of the argument. This is one of those classic stimulus setups where they throw a big conclusion indicator into the last sentence along with a conclusion. That draws your eye towards that area, and on the surface makes you think it's the main point of the argument. But it's not; it's conclusion that is then used to support the main conclusion, which is in the second sentence in this problem.

Basically, if you see a Main Point question and the last sentence looks like this one, be very careful. Because unless it's a really easy problem (like in the first 5 problems of the section), it will be a sub-conclusion. It's an effective trick, though: only about one out of every three students answers this problem correctly.

Please let me know if that helps. Good question though, because you will see this type of arrangement again.

Thanks!