Q12 - On their way from their

[mymansupa]

Hey... I am having a tough time understand why (C) is right... although it was a STRONG contender for me... and I picked (E) having doubts because the stimulus did not talk about the efficency of the ants foraging BUT the stimulus also did not talk about using an alternate form of guiding as well... Don't we have to assume that the ants are aware that their pheromones evaporate instantly as well as having a back-up guide plan to make (C) correct? I felt (E) was better supported by the stimulus to some degree because it made me assume less... Is because (E) says "Saharan ants" them indigenous to that territory when (C) says "If any ants live in the Sahara" that makes (E) incorrect??? Please help me because I need to tackle this one so I can be prepared for other questions like this... Thank you...

[giladedelman]

Thanks for posting!

We know that most ants use pheromone as a guide between food and home (personally, I use Google Maps), but that pheromone disappears almost immediately when the temperature goes over 45 degrees, as it typically does in the afternoon in the Sahara. So if you're in the Sahara on a typical afternoon, and you're an ant, chances are you're not using pheromone as a guide -- you'd have nothing to follow!

(C) is correct for that reason. If any ants live in the Sahara and only look for food in the afternoon, at which time it's typically over 45 degrees, then those ants generally (notice how typically and generally match up) don't use pheromone to guide themselves. Why not? Because the pheromone would evaporate instantly, and therefore be of no use as a guide!

We don't need to assume anything about ants' knowledge or backup plans. Maybe the ants don't have a backup plan (no Google Maps?), and they die -- we don't care! All we care about is what we can infer, and we can infer that they don't use pheromone to guide themselves, because it would be impossible.

Now, (E) is incorrect not because of the word "Saharan," but because of the discussion of efficiency. We know how the temperature affects the ants' use of pheromone, but we have no clue as to the relative efficiency of their food-foraging when they are or are not using pheromone. For all we know, they're more efficient when they rely on Google Maps instead of pheromone!

(A) is incorrect because we can't infer anything about when most ants forage for food.

(B) is incorrect because we don't know anything about "most ants that do not use pheromone."

(D) is incorrect because we have no idea what ants would use instead of pheromone. (You know what I'd suggest.)

Does that answer your question?

[mymansupa]

Perfection... thank you so much

[nthakka]

(A): Ants could forage in the afternoon in places where the temperature does not exceed 112 degrees, such as the midwest in the United States. Further, they could even forage in the afternoon where these temperatures DO exceed 112 degrees, they would just have a hard time returning back to their nest because the pheromones are gone. Therefore, (A) is incorrect.

(B): Most ants could use pheromones, they could simply choose to use these when feasible (early morning or night time, when temperature is normal). Further, they could also use these in the afternoon, it would just simply disappear due to the heat. We can eliminate (B).

(D): Different substance? Completely out of scope. Maybe they are only capable of using one substance, pheromones. We just don't know, and this is not supported by the stimulus.

(E): Introduces efficiency into the discussion, which was not mentioned anywhere in the stimulus. Ants could forage just as efficiently or even better when temperature is high, the problem is that they simply cannot return to the nest due to the disappearance of pheromones. Efficiently finding food isn't the question: being able to return to the nest is.

That leaves (C): Note the language is appropriate for the question stem. "Generally". If ants live in 112+ degree weather AND only forage during this time, we can infer that they can't use pheromones to guide themselves back to the nest, because we know the pheromones disappear when it is 112+ degrees. If something disappears, the ants can't use it. (C) is the correct answer.

[a8l367]

Just get it
In C:
Ants do not use feromones cause they are useless
I mean even if they emit feromons ants are still can't "use" them.