Insects and Drugs - RC passage from Manhattan CAT

[saurabh.atri]

Dogs are widely used by the police as biological recognition systems to detect drug smuggling and drug caches. Yet recent evidence suggests that insects, rather than mammals, might be used more effectively in this capacity. In the 1950s, German biologist Dietrich Schneider developed the first method that enabled researchers to record activity in insect olfactory nerves and to identify the compounds or class of compounds that trigger a particular behavioral response. The position of the insect olfactory organs on the surface of its body allows for direct investigation of the system’s response. Schneider’s technique formed the foundation of an olfactory detection system based upon insects, a system that is at least as effective as the ones based upon mammals.
Insects have olfactory systems that are very similar to those of vertebrates. Insects first detect odors via finger-like protuberances on the antenna, called olfactory sensilla. The odorant molecules pass through pores in the outer cuticle of the sensilla and become attached to an odorant-binding protein. This protein carries the hydrophobic molecules through the lymph fluid found inside the cell and attaches them to receptors on the dendritic projections of a sensory nerve cell. Finally, these receptors send signals to the central nervous system, allowing researchers to detect and interpret the responses.
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It can be inferred from the passage that insects would be less useful for helping researchers to detect drugs if which of the following were true?
a) They were as accurate as, but not more accurate than, dogs in detecting drugs.
b) Insect olfactory systems did not deliver odorants to nerve cells, as vertebrate olfactory systems do.
c) Dietrich Schneider did not develop the first method that enabled researchers to record the activity in insect olfactory nerves.
d) They did not have finger-like protuberances for detecting odors.
e) The signal sent to the insect’s central nervous system did not allow researchers to classify the compound that triggered the response.


OA is (E).. I agree that E is part of the reason that makes insects important in this field.
However, I do not understand how it is more relevant than (B)
b) Insect olfactory systems did not deliver odorants to nerve cells, as vertebrate olfactory systems do.

The Official Explanation states that it is not important whether or not the insect's system is similar to a dog's.
But (B) is not concerned between the similarity between how the systems function.. B says that insect olfactory systems did not deliver odorants to the nerve cells (forget about the " as animals..." as it is not an essential modifier)

E.g If I say Cats do not like to be petted, as Dogs do .. This means that Cats do not like to be petted IN CONTRAST to dogs who do like to be petted. It does not mean that Cats do not like to be petted in the same way that dogs are petted..?

.. Now if the olfactory system did not transmit the odorant molecules to nerve cells, there is a good reason to beleive that there would be no response in the insect at all when it came in conatct with some odor molecules...

Would appreciate your insights on how B, if true, does not hurt the argument more than E does.

[messi10]

But (B) is not concerned between the similarity between how the systems function.. B says that insect olfactory systems did not deliver odorants to the nerve cells (forget about the " as animals..." as it is not an essential modifier)

This is not a correct interpretation of choice B. Choice B is exactly what it says it is; you cannot ignore the part following the comma. The 'as' introduces a comparison that is very necessary for the meaning of choice B. If you remove the part after the comma, you are completely changing the meaning of the choice.

E.g If I say Cats do not like to be petted, as Dogs do .. This means that Cats do not like to be petted IN CONTRAST to dogs who do like to be petted. It does not mean that Cats do not like to be petted in the same way that dogs are petted..?

No, this is also incorrect. The 'as' used in your sentence is being used as a comparison signal and it is comparing how they like to be petted. It is not comparing dogs and cats.

[saurabh.atri]

Hi Messi10,
Thanks for your response :)
Im having a tough time agreeing with you though..
"Insect olfactory systems did not deliver odorants to nerve cells, as vertebrate olfactory systems do."
Means:
"Unlike vertebrate olfactory systems, insect Olfactory systems do not deliver odorants to nerve cells"

So, there must be some other reason based on which this choice is not correct (irrespective of what the "AS..." phrase means).

[messi10]

Hi Saurabh,

I understand why you are confused but 'like' and 'as' do not work in the same way. Like or Unlike is used to compare nouns and As, when used as a comparison, is used to compare clauses.

By using unlike, you are changing the meaning of choice B. You end up comparing insect olfactory systems to vertebrate olfactory systems. Choice B on the other hand uses 'as' to indicate the way in which they deliver odorants is different.

Also, since this is a Manhattan CAT verbal, I don't think there is any other reason why choice B is incorrect other than the one stated. The reason I say this is because with Official Guide, it is speculated that the people who write the questions are not the ones who write the answer explanations. So a lot of questions lack good explanations. But with Manhattan CATs, I don't think this is the case.

However, perhaps you have a point in that it is a confusing answer choice. An instructor will respond to your query and if you have a valid case, they may change it. But in my opinion, its quite clear in what it is trying to say.

[saurabh.atri]

Would appreciate some expert input... No offence messi10.. Just need to put my mind at ease here

[tim]

The question asks what would make insects less useful for detecting drugs. In other words we need to focus on the end result. E does that, whereas B merely focuses on the process used to achieve the end result. We don't care about the process though, just the end result.