LSAT 77, Reading Comprehension, Q21, LSATHacks

RC Question 21 Explanation, by LSATHacks

QUESTION TEXT: The author most likely calls a certain kind of…

DISCUSSION: This question quotes line 25. If you read the lines around that, you’ll see that the “typo” happens when the information in DNA is being copied into RNA. So it’s a copying error. But it’s a significant copying error, since it’s these “typos” that let the body find new defenses against diseases.

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1. Huh? If you read lines 27-29, you’ll see that these mutations are what allow the immune system to adapt to new diseases.
2. Not at all. These mutations are what allow our bodies to adapt solutions to fight off infections. The right “typo” can let you defeat a serious infection.
   And I’m sure you’ve seen a “minor” autocorrect typo that completely changes the meaning of a text you sent.
3. CORRECT. DNA has certain information. But the body needs to invent new solutions to fight new diseases. So DNA makes small copying errors when copying information to RNA. These “errors” let the body invent new defenses. If one works, they’ll mass produce it.
4. Nothing in the passage suggests this. It sounds like scientists have been able to easily find the mutations. After all, these mutations are what let immune cells test defenses against a variety of diseases; their effects should be highly visible.
5. This answer just throws together a bunch of big words to confuse you. But it has no support in the passage – the author doesn’t even mention textual analysis!