Correct: A

Incorrect: C

https://classic.7sage.com/lsat_explanations/lsat-53-section-1-question-09/

"C" is incorrect because the male population could've stayed the same and the decline of the female population made it equal to the male population. "A" is correct because "proportional" gives relation to the whole population. It is saying that the decline of the female population is a decline in the total population. This takes it from being 2/3 of just females to 2/3 of the species.

Correct: D

Incorrect: E

https://classic.7sage.com/lsat_explanations/lsat-53-section-1-question-08/

Explanation: "D" makes it where we can't say that the effects go away with age. By saying that the 2nd and 3rd studies were flawed, we can take away the conclusion that is based on those results. "E" doesn't specify how many children slept with nightlights and weren't nearsighted. "E" could have 5 children that were nearsighted and slept with nightlights along with 95 children that slept with nightlights and were not nearsighted. Because we don't know if the other children were nearsighted even though they didn't sleep with nightlights, or slept with nightlights and weren't nearsighted, or not nearsighted and didn't sleep with nightlights, we can't form a conclusion on partial results. It just talks about several older children that were nearsighted and slept with nightlights. That's not enough say that nearsightedness caused by nightlights goes away with age.