According to the passage, the dimorphic wing structure of the summer generation of water bugs occurs because

Julie on August 28, 2019

Answer Explanation

Hi LSAT Max, What textual evidence would lead us to the correct answer? Thanks!

2 Replies

Irina on August 30, 2019


The passage tells us that the dimorphic wing structure of the summer generation occurs due to to the developmental response to the temperature to which developing eggs are exposed to being laid, it is not genetically determined. (lines 43-49). Eggs laid by the overwintering adults (summer generation) are formed in early autumn and early spring. Those formed in autumn are exposed to cold winter temperatures and produce micropterous adults, whereas the eggs formed in the spring are never exposed to cold, and thus yield individuals with macropterous wings (lines 55-63). (A) correctly summarizes this information outlined in the passage.

Let's look at the other answer choices:

(B) the eggs that produce micropterous and macropterous adults are morphologically different.

Incorrect. The passage never talks about whether the eggs themselves are different only that eggs exposed to warm/ cold temperatures produce morphologically different adults.

(C) water bugs respond to seasonal changes by making an acclimatory functional adjustment in the wings.

Incorrect. The differences in wing structures are an example of a developmental response rather than acclimatory (lines 16-21).

(D) water bugs hatching in the spring live out their life spans in ponds and never fly.

Incorrect. Bugs hatching in the spring usually do not live the ponds, but small ponds occasionally dry up, forcing the water bugs to fly (lines 32-42).

(E) the overwintering generation, which produces eggs developing into the dimorphic generation, spends the winter in the forest and the spring in small ponds.

Incorrect. This statement is factually correct - the second-generation does spend winter in the forests and returns to small bodies of water in the spring (lines 26-30). But what does this have to do with the question? The dimorphic wing structure occurs due to eggs' developmental response in temperature changes not due to the habitat of the adult water bugs.

Does this make sense?

Let me know if you have any further questions.

Julie on September 3, 2019

I understand the question now and where I went wrong! I really appreciate the explanation, thank you so much!