We should recognize this as a strengthening question, since it asks us: Which one of the following, if true, would most support the researcher’s hypothesis?
We should know right from the get go that we are dealing with a strengthening question that involves a hypothesis, just based off of the question stem. As a reminder, whenever our conclusion is a hypothesis, an answer choice which eliminates an alternate hypothesis will always strengthen our argument. As we read our stimulus, we should be on the lookout for what it is our hypothesis is trying to explain; what is our phenomenon?
Our stimulus begins with essentially a definition of pit vipers; they are vipers with pits on the sides of their head which give them a thermal (think heat) impression of their environment. Interesting! This is our phenomenon; pit vipers have infrared sensors. We next learn about a prior hypothesis, an explanation for why this is the case. Scientists used to believe that the explanation for why pit vipers have their pits is that it helps them find prey, because all pit vipers are predators. However, the hypothesis we are tasked with supporting is that of a researcher who believes the pits are actually for detecting the pit viper’s predators.
What we have to remember is that predator and prey, similar to premise and conclusion, are relata. Just as the same sentence can be both a premise and a conclusion relative to other parts of the same argument, an animal can both be prey (relative to its predators) and a predator (relative to its prey). So although the scientists were right that all pit vipers are predators, they forgot that they are also all prey! So we now have two explanations for why the pit vipers have pits which have equivalent support. Our job is to tip the scales in favor of the detecting predators hypothesis. Let’s see what we get:
Answer Choice (A) This gives us a comparative of the pit viper genders which tells us none of their differences, but only traits they both share. We already knew they had infrared sensors, so all we learn is that they exhibit both aggressive and defensive behavior. The problem is that this could both support that the pits are for spotting prey (aggressive) or for evading predators (defensive), and in either case the support is incredibly small.
Correct Answer Choice (B) This is what we would expect to be true if the pits were for evading predators and not for finding prey! What this answer essential gives us is a correlation; having pits correlates with markedly different defense strategies. It also gives us the absence of a correlation between having pits and different predatory behavior. This tips the scale in favor of our avoiding predators hypothesis!
Answer Choice (C) But why do they have the pits!
Answer Choice (D) Interesting, but this does nothing to explain why they might have the pits, and whether it relates to avoiding predators.
Answer Choice (E) C, D, and E all introduce some new factor (venom, smell, and rattles) without giving us any information that could support that pit vipers have their pits to avoid predators.