October 1991 LSAT Section 4 Question 20

Normal full–term babies are all born with certain instinctive reflexes that disappear by the age of two months. Becau...

Matthew12 on December 7, 2020

Can someone explain the logical structure of the premise/conclusion in the question and how that coincides with the correct answer?

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NS1 on March 10, 2021

^I have the same question as above. Got the question correct due to ABC diagramming, but wanted to know if that is the best method.

Emil-Kunkin on August 25 at 09:20PM

The passage sets up a scenario where we have a general rule and then a specific application of that rule.

We are told that all members of a class (normal full term babies) possess a certain trait ( losing reflexes by month 2). We are then told that since this individual lacks that trait (still has reflexes ), this individual isn't a member of the aforementioned class.

We are looking for the same structure: all members have a trait, X doesn't have this trait, so X isn't a member.

This is a match form D. D tells us that all members of a class have a pouch, and that since X doesn't have a pouch, it's not a member of the class opossum.