Australian researchers have discovered electroreceptors (sensory organ

GMATNInja, please help
For Q3, still not able to understand how to eliminate B. In the function role we could think of understanding 1st paragraph with or without the tactile receptor. When both (snout & tactile ) are there, it simply answers the question that "Yes"there is an additional organ that responds to electronic stimuli. When tactile is not present, it means only "snout" organ responds to electronic stimuli.

Hence B makes sense...moreover identical, though literally means exact replica, can be also used in the sense of serving similar function(tho not exact)....Hence still don't think "identical" as a strong language.Please provide some color on the same

While I do agree with A as a potential choice but somehow this does not become too apparent. By responding to stimuli, understand that we won't be able to distinguish between snout's or tactile's response and hence it makes sense to eliminate an alternative explanation, however somehow B looks more appealing/tempting.

3. The author of the passage most probably discusses the function of tactile receptors (lines 7-11) [While it is true that tactile receptors, another kind of sensory organ on the anteater’s snout, can also respond to electrical stimuli, such receptors do so only in response to electrical field strengths about 1,000 times greater than those known to excite electroreceptors.] in order to

(A) eliminate an alternative explanation of anteaters’ response to electrical stimuli
(B) highlight a type of sensory organ that has a function identical to that of electroreceptors

Dear Experts,

I have a doubt in question 2
Which of the following can be inferred about the experiment described in the first paragraph ?

Lets see first paragraph only.

Now mentioned OA is C.

How to infer this ?

looking for explanation of q no 4

Hi pragya007,


4. Which of the following can be inferred about anteaters from the behavioral experiment mentioned in the second paragraph?

(A) They are unable to distinguish between stimuli detected by their electroreceptors and stimuli detected by their tactile receptors.
(B) They are unable to distinguish between the electrical signals emanating from termite mounds and those emanating from ant nests.
(C) They can be trained to recognize consistently the presence of a particular stimulus.
(D) They react more readily to strong than to weak stimuli.
(E) They are more efficient at detecting stimuli in a controlled environment than in a natural environment.mn


Correct Answer: C,
Explanation: We can directly infer option C from the following lines in the passage.:"In one behavioral experiment, researchers successfully trained an anteater to distinguish between two troughs of water, one with a weak electrical field and the other with none.".
Option A is incorrect, since the experiment was not performed for testing the detection by their tactile receptors.
Option B is incorrect, as though they were unable to distinguish between the electrical signals emanating from termite mounds, but they did observe anteaters breaking into a nest of ants at an oblique angle and quickly locating nesting chambers.
Option D & E : clearly incorrect, as not discussed in the passage.


Hope this Helps.
Thanks.

VeritasKarishma
please explain question 2 & 5

Hi saby1410,

Not sure if you are still looking for Answers, but you could refer the below answers by experts here:

For Question 2:

https://gmatclub.com/forum/australian-researchers-have-discovered-electroreceptors-sensory-organ-138945.html#p1246597
https://gmatclub.com/forum/australian-researchers-have-discovered-electroreceptors-sensory-organ-138945.html#p2070149

For Question 5:
https://gmatclub.com/forum/australian-researchers-have-discovered-electroreceptors-sensory-organ-138945.html#p2097486

Let me know if you still have doubts.
Thanks.

VeritasKarishma GMATNinja,

How can we eliminate option D in Q6.

"Anteaters are observed using various angles to break into nests of ants."

It confirms that the angle to break depends on something.

What is that something? Your answer would be electrical signals, but the scientists are yet to detect electrical signals coming from the prey's nest. The question is "which of the following most strengthens?". The author has already stated the scientist lack certain evidence in their hypothesis. The discovery of that certain evidence definitely strengthens the hypothesis. Also, multiple angles don't really help the theory. It is possible that the anteater's need to break in at a certain angle, it is also possible that the angle might vary - either way, the variation, or the lack of it, doesn't impact our theory a lot and definitely not as much as option B.

Hey EuropaGust,


In CR lingo, what we are looking for in Question 6 is a strengthener - some new information (which of the following, if true - means not information we already know to be true from the passage!) would most strengthen the hypothesis made?

Conclusion/Hypothesis here: anteaters use electroreceptors to detect electrical signals given off by prey

What we already know from the passage:
1. On one side, so far, electrical signals have not been detected from termite mounds
2. On the other side, ant-eaters are able to attack nests at an oblique angle and locate nesting chambers quickly

What new information will support this hypothesis?

What if weak electrical signals now get detected from the nesting chambers (where the ants are nesting)? Then, it would support the idea that ant-eaters are able to detect these signals from the nesting ants thanks to the electro-receptors, which is why they are able to figure out better attack angles, and quickly locate these chambers.

This is why option B works as a strengthener. Now, let us look at option D.

(D) Anteaters are observed using various angles to break into nests of ants.

So what? All this tells us is that anteaters seem to have some ability to figure out optimum angles (probably). And as you correctly point out, this indicates that there is "something" which helps them figure out optimum angles.

But this "something" could be anything! Maybe electro-receptors picking up weak signals, or maybe a thermal factor (maybe ant body heat from the nesting area is being picked up by heat sensors in anteaters!). Option D only indicates that there could be something - it is not enough to support the hypothesis that it is that something is electro-receptors picking up weak electrical signals from prey in nesting areas. Hence, option D as it stands is not good enough to be considered as supporting or strengthening the hypothesis.


Hope this helps!

Regards
Harsha
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GMATNinja, BrightOutlookJenn, can you please explain Qs 3,5, and 6?

For Q3, I originally selected E. Tact recept has not been discussed in the original experiment. Author demonstrates different response rate as a result of bringing tact recept. Therefore, I assume A is correct> However, I don't have a clear rationale why E should be eliminated.

For Q 5, I selected A originally. I eliminated E because I did not see how the speed to locate the prey may be relevant to this question.

For Q6, can you please explain why A should be eliminated?

Question 3

Question 3 asks us why the author brings up tactile receptors. How does it fit into the author's overall point?

In the first paragraph, the author tells us how researchers made a certain discovery -- they exposed the anteaters' snouts to "extremely weak electrical fields" and saw that the brain responded.

Then the author discusses tactile receptors: it turns out that these, too, can sense electrical fields! That's kind of a problem for the researchers -- how do we know that the anteaters really have electroreceptors if tactile receptors can do the same thing?

The author explains that the tactile receptors only respond to stronger electrical fields. This means that the researchers' findings are solid, because they used weak electrical fields that wouldn't excite the tactile receptors.

So, what was the purpose of bringing up tactile receptors at all? Just to rule them out as a possible explanation for the researchers' finding. That's exactly what (A) says, so (A) is the correct answer to question 3.

(E), on the other hand, really doesn't capture the author's purpose -- he/she isn't trying to say "look, these researchers kind of suck because they missed this other factor." The author is actually trying to strengthen the researchers' claim by saying that they did exclude this other factor. By using such weak electrical fields, the researchers ensured that their findings point toward electroreceptors instead of tactile receptors. Eliminate (E) for question 3.

Question 5

When a question mentions a specific detail from the passage, it's a good idea to go back and re-read the exact language of that detail. Question 5 asks about a certain experiment, so here's what the passage says about that experiment:

As you can see, speed plays a huge role in the interpretation of this experiment. Because the anteaters were so quick to locate nesting chambers of their prey, the researchers believe that they used electroreceptors in the hunt.

The researchers would agree that "the speed with which the anteaters located their prey is greater than what might be expected on the basis of chance alone." So, (E) is the correct answer to question 5.

Question 6

Here's question 6:

And here's (A):

In paragraph 1, the author tells us that tactile receptors can detect strong electrical signals. So, if anteaters can be trained to sense chambers with strong electrical signals, it's possible that the animals are using tactile sensors to do so instead of electroreceptors. We want to specifically strengthen the argument that the anteaters use electroreceptors, and working with a strong electrical current wouldn't definitively strengthen that argument.

Eliminate (A) for question 6.

I hope that helps!
_________________

6. Which of the following, if true, would most strengthen the hypothesis mentioned in lines 17-19 [Such evidence is consistent with researchers’ hypothesis that anteaters use electroreceptors to detect electrical signals given off by prey]?

(A) Researchers are able to train anteaters to break into an underground chamber that is emitting a strong electrical signal.
(B) Researchers are able to detect a weak electrical signal emanating from the nesting chamber of an ant colony.
(C) Anteaters are observed taking increasingly longer amounts of time to locate the nesting chambers of ants.
(D) Anteaters are observed using various angles to break into nests of ants.
(E) Anteaters are observed using the same angle used with nests of ants to break into the nests of other types of prey

isnt it anteaters instead ? I got confused for this one, because it's an easy B, and I chose A because I thought this make no sense that the researchers are able to detect weak signal ?

Question 6

Think of the situation from the researchers' perspective: they hypothesize that anteaters use their electroreceptors to locate prey. After all, anteaters quickly locate nesting chambers of ants that can't be seen!

Unfortunately, researchers haven't yet detected an electrical signal emanating from the ants' nesting chambers. So, while we know that anteaters can't see the chambers, we have no evidence that they are using electrical signals to locate those chambers.

If researchers did some more testing and found out that there are, indeed, weak electrical signals emanating from the nesting chamber of an ant colony, then that would certainly support their hypothesis about electroreceptors.

(B) would support the researchers' hypothesis, so (B) is the correct answer to question 6.

Here's (A):

From the passage, we know that two kinds of receptors respond to strong electrical signals: electroreceptors and tactile receptors.

On the other hand, only electroreceptors respond to weak electrical signals.

We're trying to support the hypothesis that the anteaters are using electroreceptors to find prey. Even if researchers can train anteaters to respond to strong electrical signals, as stated in (A), that doesn't really help this hypothesis -- we wouldn't be able to tell whether the anteaters were relying on their tactile receptors or their electroreceptors to find the chambers.

Because (A) wouldn't provide evidence to support the hypothesis for electroreceptors in particular, we can eliminate (A).

I hope that helps!
_________________

In Q6 -> I wanted to know why option B is the correct one.

Just because the Researches are able to detect a weak signal, how does that imply that anteaters use electroreceptors to detect signals given off by prey?

Is there any such statement given to imply this conclusion in the passage that I'm missing to notice? Please let me know if there's a gap that I'm missing to notice anywhere.

Best.

Question 6

In the second paragraph, we learn the following key facts:

• Anteaters can likely detect weak electrical signals
• Anteaters can break into ant nests and quickly locate the nesting chambers

According to researchers, the second fact suggests that anteaters use electroreceptors to locate the nesting chambers.

Now here's (B) again:


The correct answer should support the hypothesis that "anteaters use electroreceptors to detect electrical signals given off by prey?" So how does (B) affect this hypothesis?

Well, we already know that anteaters can detect weak electrical signals, and that they can break into the nesting chambers of ant colonies. So if the nesting chambers of ant colonies give off weak electrical signals, this supports the idea that anteaters are using electroreceptors to detect prey.

Without (B), we'd have no idea whether ant colonies give off weak electrical signals or not. If they didn't, that would weaken the hypothesis. Since (B) confirms that ant colonies do give off weak electrical signals, it strengthens the hypothesis that anteaters use electroreceptors to detect them.

Of course, while (B) strengthens the researchers' hypothesis, it doesn't prove the hypothesis to be true. Put another way -- just because the ant colonies give off weak electrical signals doesn't necessarily mean the anteaters are detecting them with electroreceptors. Nonetheless, (B) does strengthen the argument.

For that reason, (B) is correct.

I hope that helps!
_________________

GMATNinja KarishmaB
Why Q2 E is correct?
(E) Researchers tested small areas of the anteater’s snout in order to ensure that only electroreceptors were responding to the stimulus.

Nowhere mentioned the intent of testing a small area of snout. How can we infer E that researchers wanted to ensure something and that's why they were testing a small area.
Please explain.

Thanks for your time!

KarishmaB GMATNinja

For Q5, I agree that speed is the focus of the discussion. But why A is incorrect?

(A) The event they observed provides conclusive evidence that anteaters use their electroreceptors to locate unseen prey.

Is it bcz they have used a very strong word ""conclusion evidence"?
The hypothesis suggest that anteaters use electroreceptors to locate unseen prey. So now when they saw anteaters break into a nest, they are more confident that anteaters were using their electroreceptors to locate the nesting chambers.
It is also support by last line of the para.

Could you please explain why A is incorrect then?

Question 2

Good question! Actually, the correct answer is not (E) for exactly the reason you said: we really can't say why the researchers exposed only "small areas" of the anteater's snout to electrical fields. And we definitely can't conclude it was because the scientists wanted to only stimulate electroreceptors. So we can eliminate (E).

Let's now take a look at (C):


We are told that researcher's found that the electroreceptors are clustered at the "tip of the spiny anteater's snout." They discovered this by testing small areas of the snout. So if only the tip is sensitive, the researchers must have found some areas that were NOT sensitive to electrical stimulus. For that reason, (C) is correct.

Question 5

Let's consider answer choice (A):


How did the researchers feel about the "event" they observed? To figure this out, let's examine the last sentence of paragraph 2:


According to this sentence, the researchers believe that the event suggests that anteaters are using electroreceptors to locate unseen prey. Does the word "suggests" mean that the researchers consider this to be "conclusive evidence?"

Well, conclusive evidence means that it leaves no room at all for doubt. This evidence, on the other hand, only "suggests." In other words, it supports the idea that anteaters are using their electroreceptors. But just because it provides support doesn't mean that the evidence is conclusive. For that reason, we can eliminate (A).

I hope that helps!
_________________

I think Q3 answer C is not worded clearly. Instead of "some areas", it should say areas where tactile receptors are present. Otherwise, how do we make connections to tactile receptors? By looking at "not sensitive to a weak electrical stimulus"?

Or, does this sentence mean there are areas in snout which don't have any receptors at all? And they "found" it implicitly? Even if their actual focus was finding electroceptors?