#19 - Concept Reference, Must Be True

[Administrator]

Complete Question Explanation

The correct answer choice is (E).

Answer choice (A):

Answer choice (B):

Answer choice (C):

Answer choice (D):

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


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

[lsatquestions]

Hello,

I narrowed the choices down to D and E, but ultimately selected D. Is D incorrect because the differences are not 'genetically determined' and are instead adaptive? I see why E is correct as autumn formed eggs are exposed to colder temperatures and form more micropterous wings.

[Adam Tyson]

Correct! The differences are determined not by genetics, but by environment, specifically temperature. See this line in the last paragraph:

The dimorphism of micropterous and macropterous individuals in the summer generation expresses developmental flexibility; it is not genetically determined.

[taketwo]

Hello! I am very confused on this question (and on this RC). I am wondering why C is incorrect, because the third paragraph states “those eggs formed in autumn are exposed to cold winter temperatures, and thus produce micropterous adults in the summer generation." which means that they can’t fly. Is E correct because the water bugs hatched in summer are dimorphic (macropterous and micropterous) whereas those hatched in spring are micropterous? Paragraph 3 states that “those eggs formed in august are exposed to cold winter temperatures, and thus produce micropterous adults in the summer generation.” I got really confused on this section because it seemed like the water bugs could hatch at different times and be in the early generation, overwinter generation, or summer generation and I had a really hard keeping track of the requirements for each.

[Adam Tyson]

The question asks about the bugs that hatch during the summer, taketwo, and this line from the second paragraph should help:

The eggs laid in the summer hatch and develop into adults in late summer.

That describes the bugs that form the overwintering brood, the ones that form their eggs in autumn and spring. Now, this line from the third paragraph adds more helpful info:

Eggs producing the overwintering brood are all formed during the late summer's warm temperatures.

Thus, the eggs that hatch during the summer will all produce macropterous individuals, while the eggs that hatch in the spring come from two batches: those formed in the autumn, which are exposed to cold temps and form micropterous individuals, and those formed in spring that are only exposed to warmer temps and thus produce macropterous bugs.

So, the ones that hatch in summer will be 100% macropterous, while those that hatch in spring will be a mix of both types. That's why E is the correct answer.

C is an opposite answer, since the ones that hatch in the summer will all have normal wings and be able to fly to the forests for the winter.