#17 - Concept Reference, Must Be True

[Administrator]

Complete Question Explanation

The correct answer choice is (A).

Answer choice (A): This is the correct answer choice.

Answer choice (B):

Answer choice (C):

Answer choice (D):

Answer choice (E):


This explanation is still in progress. Please post any questions below!

[vangorgc]

Hi PowerScore -
When seeing this question for the first time, I immediately ruled out the first answer because nowhere (that I had or have since found) does the passage mention two different sets of eggs. It does say that some of the eggs hatch to have no wings to fly with, and some hatch with long wings to fly with, but it doesn't say this is because there are two different sets of eggs.
How would you infer answer A from the text?
Thanks -
Grace

[Robert Carroll]

Grace,

You're making more of "sets" than is in the word itself. A "set" of eggs is just a collection of eggs. As you point out, some eggs hatch into bugs with small wings, some into bugs with large wings. Lines 58-63 tell us why a bug may develop large wings - if the egg is formed in early autumn, it is exposed to cold temperatures, and if formed in early spring, it is never exposed to cold temperatures. "Eggs formed in autumn" and "eggs formed in spring" are the two sets of eggs, differentiated by when they are formed. There is nothing in the word "set" that indicates we can't form the idea of a set by a kind of definition. If, say, questions 20, 23, and 27 were the only hard questions in a section, then the section has two "sets" of questions: the easy ones (1-19, 21, 22, 24-26) and the hard ones (20, 23, 27). The questions don't have to be clustered in order, or have any other concrete property, to be able to form a set. Similarly, the eggs can be divided into "exposed to cold by being formed in autumn" and "never exposed to cold by being formed in spring", and that is the relevant difference between eggs that leads to a difference in wing size.

Answer choice (A) is describing what it means, and all it means, by "sets of eggs" with the statement after the comma. These "sets" are being created by defining what it means to be in each set.

Robert Carroll

[timmer]

I agree with Grace,

I can argue for why A is the correct answer, but there appear to be problems with the answer.

I have to believe there is a typo somewhere but by using the keyword Because we know we need an explanatory answer and the other answers don't make sense.

Specifically
B cannot be right because eggs are not morphologically different (That is the whole point of the passage)
C Acclimatory adjustments are reversable and cannot be used to justify any answer with wings.
D "Never need to fly." is directly contradicted by the text, so we know it's untrue, and more importantly wouldn't support a dimorphic wing structure, it would support a no-wing structure.
E is a likely a true statement and a good inference or MSS answer. Its explanatory powers are weak and require assumptions.

A: The strongest explanatory power: that is in line with the mechanism of developmental response due to temperature.

However, There is no support that the overwintering generation lays two sets of eggs. OR that it lays one set, and it hatches at different times. There is direct support to suppose the opposite as we know that spring/summer waterbug also lays eggs AND we are told that there are two generations per year.

I'm not really how we can get these facts to add up to 2 generations per year. I think it's reasonable to say it's a bad question and you can still score high if you get it wrong. I think it takes a certain framework, which might be LSAT specific to divine that A is the right answer.

I could be totally wrong, but I didnt' find the "set" answer to be a compelling .

[Jeff Wren]

Hi timmer,

This passage, the infamous Water Bugs passage, is generally considered one of the hardest reading comp passages of all time (and is actually on our list of the hardest RC passages of all time), so don't feel bad if this passage seemed confusing.

First, Answer A doesn't say that the overwintering generation lays two sets of eggs, it says that the overwintering generation forms two sets of eggs. You may be wondering why I'm mentioning this difference in wording and whether it matters. It does.

The passage states that "Eggs laid by the overwintering adults in the spring, which develop into the summer generation of adults, are formed (my emphasis) in early autumn and early spring" (lines 55-58).

The eggs that are formed in early autumn are one set, and the eggs formed in early spring are the other set. Even though they are all laid in the spring, they are formed at two different times. This point is very important, but it is also very easy to miss.

The passage then goes on to explain that the eggs formed in autumn (and exposed to the cold winter temperatures) produce micropterous (little wings) adults and those formed in spring (and never exposed to cold winter temperatures) produce macropterous (normal wings) adults.

Answer A perfectly captures this key idea of the passage, namely that when the eggs are formed (and more specifically whether they are exposed to cold temperatures) determines their wing type.

One final point, while you're correct that there are two generations per year, that is a separate issue in a sense. In other words, what this question is asking about is the differences in the wing types found in one of generations, the summer (early) generation. I only mention this because sometimes students assume the two different wing types correspond to the two different generations, which may seem reasonable, but is not what actually happens.