Logical reasoning PrepTest 140 · Section 2 · Question 10

Incorrect. This answer reverses the relationships that the argument relies on. There, the failure to address problems is assumed to be connected to stress, which suppresses the immune system and thus leads to gum disease. It's not the painful condition (gum disease) that causes one to avoid dealing with problems.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with Necessary Premise

Stimulus Summary:
Study Ð Those who directly address problems have less gum disease than those who don't.
Stress suppresses the immune system
Therefore Ð Immune system suppression causes gum disease

Answer Anticipation:
Let's start with the conclusion and work backwards to identify where the gap is. That conclusion states a causal relationship—suppression of the immune system causes gum disease.

Unpacking this in the context of the premises, we can see that the suppression of the immune system is established as being related to stress, and gum disease is associated with refusing to think about problems. However, these two ideas are never directly related—there's no connection drawn between avoiding problems and having stress. Maybe those who avoid problems do so because it lowers their stress levels!

Since the argument concludes a connection between immune suppression and gum disease, and the premises connect these ideas to stress and avoiding problems, the argument assumes that connection between stress and avoiding problems, so the correct answer should highlight it.

Answer Explanation:
This answer connects the terms that the argument assumes are connected. If those who refuse to think about problems have higher stress levels and higher levels of gum disease, and high stress levels are known to suppress the immune system, then there's a connection between gum disease and immune system suppression which the conclusion requires. If refusing to think about a problem doesn't contribute to stress levels, then there is no such connection and the argument falls apart.

Key Takeaway:
When a Strengthen with Necessary Premise question has a series of connections, follow them to see where they end and what connection is missing from the argument. The correct answer will almost certainly directly address that connection.

Incorrect. This answer hurts the argument by connecting high stress levels and thus immune system suppression to those who suffer gum disease at a lower rate.

Incorrect. This answer suggests a separate reason for the lower levels of gum disease other than stress levels/immune suppression—the group with the lower levels addresses gum disease like any other problem and deals with it quickly.

Incorrect. What matters is whether these people thus face higher stress levels, not whether they find addressing problems to be stressful. This answer has a jump between what people believe and what is true.