A common genetic mutation

Answer choices

1. A

   Too Strong: "only way"12% picked this

   Restoring cathepsin C to normal levels is the only way to

   The author is assuming that this is one way to eliminate periodontitis, but there's no way to support the idea that the author thinks it is the only way. In other wording, she does assume this method is Sufficient. She doesn't assume it's Necessary.

   12%
2. B

   Too Strong4% picked this

   Genetic mutation is the only cause of lowered levels of

   Too Strong: "only cause of low cathepsin C" It wouldn't trouble this author's argument if there were other sources of low cathepsin C, because the solution the researchers devise could presumably also help restore their enzyme to normal levels too.

   4%
3. C

   Too Strong: "soon"2% picked this

   Researchers will soon succeed in finding means of restoring cathepsin C

   There's no timeline on the conclusion / argument. It's just "once we get a solution, then periodontitis will be gone". The author never promises or insinuates that we'll get there soon.

   2%
4. D

   Too Strong11% picked this

   Persons who do not have the genetic mutation that lowers levels of cathepsin C do

   Too Strong: "nobody else gets gum disease" This is pretty tempting, similar to how choice (B) is. When you negate them, they definitely raise doubt about the conclusion. For (B), if there are other ways to get low cathepsin C, then maybe those people would still get gum disease (because maybe the solution researchers devise for mutation-caused low cathepsin C wouldn't work for them). For (D), if there are people without the mutation that do get gum disease, then maybe they would still have gum disease, even in a world where we could restore your cathepsin C levels to normal. However, negating this answer certainly doesn't weaken as much as negating choice (E). With (D), it's possible that people who don't have the mutation but do get gum disease are still getting gum disease from low cathepsin C (something other than genetic mutation causes them to have low cathepsin C). In that case, the solution the researchers devise should be able to help these non-mutation people as well. If this answer were re-written as, "Persons who do not have lower levels of cathepsin C do not get gum disease", it would be correct.

   11%
5. E

   Correct72% picked this

   A person whose cathepsin C level has been restored to normal will not

   Why this is right

   The author was definitely thinking that if we restore the enzyme to normal levels, we'll eliminate their periodontitis. If we negate this answer, it says, "Even once you restore someone's cathepsin C levels to normal, they will still suffer from periodontitis", which would destroy the conclusion.

   Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

   72%