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## #17 - Concept Reference, Must Be True

• PowerScore Staff
• Posts: 8203
• Joined: Feb 02, 2011
#78748
Complete Question Explanation

The correct answer choice is (A).

This explanation is still in progress. Please post any questions below!
vangorgc
• Posts: 12
• Joined: Nov 14, 2020
#83180
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
• PowerScore Staff
• Posts: 939
• Joined: Dec 06, 2013
#83478
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
• Posts: 103
• Joined: May 21, 2019
#88117
I felt the text that Robert quoted about the usage of the word "set" has nothing to do with this question. The two sets that are formed in summer/autumn and in spring, as he pointed out, are indeed two different sets, since they were laid by the summer generation and the overwintering generation respectively. However, the "two sets of eggs" in Q17 refer to the eggs laid by the overwintering generation only.

I think the difficulty in this question is the distraction in line 43, "[t]he dimorphism of micropterous and macropterous individuals in the summer generation expresses developmental flexibility; it is not genetically determined."

This passage is heavy on the classic "nature v. nurture" debate. But people usually distinguish these as before birth (nature - genetically determined) versus after birth (nurture/environment). So on the face of it, (A) sounds like describing two sets of eggs that are genetically different. But the passage makes it clear that environmental conditions includes the time, "in which developing eggs are exposed prior to their being laid" - i.e., before birth.

In addition, it is difficult to see that the author is implying the macropterous v. micropterous dimorphism is determined SOLELY by temperature, without any randomness.

I think (A) is the direct cause, while "(D), water bugs hatching in the spring live out their life spans in ponds and never need to fly" might be an ultimate cause according to Darwinian evolutionism - the summer generation does not need to disperse to overwinter in forests, but usually live in the ponds their whole life. The reason that some macropterous wings are still developed in this summer generation is because some small ponds occasionally dry up during the summer, which necessitates macropterous wings. Any thoughts? Thanks!

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