Logical reasoning PrepTest 107 · Section 3 · Question 5

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
Temp of ocean over 26C to 60m → Increased risk of tropical storm
CO2 keeps going up → More oceans will be over 26C to 60m

Answer Anticipation:
Must Be True questions frequently deal with conditional logic, or at least the connection between different statements that share common terms. This stimulus very much falls into that category. Using language such as "whenever" and "If" makes it conditional, though even if you didn't diagram it out, you still should have noted that the two statements overlap in that both discuss large bodies of water being over 26C to a certain depth.

The stimulus establishes that an increase in CO2 levels will cause more large bodies of water to hit that temperature up to that depth, and that when that happens, the risk of tropical storms in the area increases. As such, we can infer that if there's a continued increase in CO2 levels, then there will be an increase in the overall risk of tropical storms in various areas (and thus an increase in tropical storms). Let's find an answer stating that.

Answer Explanation:
This answer connects the two statements from the stimulus. Since an increase in CO2 will result in an increase in the number of large bodies of water at 26C to 60m, and that will result in an increased risk of tropical storms (likely resulting in there actually being more storms), this answer is supported.

Key Takeaway:
In Must Be True questions, always look for concepts that show up in multiple statements. By identifying these connections, you can derive inferences about the connection between other concepts and thus better anticipate correct answers.

Incorrect. The stimulus talks about the water temperature being over 26C, not the air temperature. Additionally, the stimulus establishes this as a sufficient condition for the increased risk of storms, not a necessary one ("only when").

Incorrect. The stimulus speaks only in relative language—things will increase from where they currently are if certain conditions are met. It never makes a strong enough statement to justify a conclusion that water temperatures have never been higher!

Incorrect. There's no discussion of tropical storm ferocity, just frequency, so this answer is out of scope.

Incorrect. This answer reverses the relationship in the stimulus, where an increase in CO2 in the atmosphere heralded hotter bodies of water. (Note that this discussing oceans isn't a problem, as they qualify as a large body of water, so if large bodies of water did have an effect, then oceans would have that effect.)