Logical reasoning PrepTest 151 · Section 2 · Question 20

Incorrect. This answer choice discusses efficiency in pollinating any of a number of plant species, whereas the stimulus only talks about efficiency in pollinating cranberries.

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
For cranberry pollination, bumblebees are more efficient than honeybees. Why? Bumblebees stay close to home and only visit a few plant species; honeybees are wandering souls and like a variety of species.

Answer Anticipation:
The correct answer will probably tie the two given facts together, explaining how not traveling/only visiting a few plant species leads to increased efficiency in pollinating cranberries (or the inverse).

Answer Explanation:
Since the author of the argument establishes causality—"This is because"—we can infer that the reasons stated are directly related to the comparison drawn. Here, since the variety of species of plant visited is listed as a cause of the honeybees lower efficiency (and the inverse of the bumblebees higher efficiency), we can infer that the variety of plants visited affects the efficiency.

Key Takeaway:
Generally, causal answers are incorrect in Must Be True questions. The exception to that, which we see in this case, is when one of the facts in the stimulus itself is causal. If you notice a causal statement in the stimulus of a Must Be True question, there's a good chance it'll lead you to the correct answer.

Incorrect. This answer seems to be contradicted by the information we learn about the honeybee, which flies over a broader area while visiting more plant species than a bumblebee.

Incorrect. First, there's no indication that cranberries are concentrated in limited areas, just that a bumblebee would stick to a limited area. Those bumblebees might do an efficient job of pollinating a small area of the total cranberry bog (yes, they grow in bogs). Second, it's not inferable that honeybees would be unlikely to visit a given area, just that they're less likely to stay nearby once there.

Incorrect. While bumblebees might be more likely to visit a second cranberry plant in a given crop since they don't travel as far, that doesn't mean they're more likely to visit that first cranberry plant than a honeybee. Maybe both types of bee are as likely to visit a cranberry crop, but the honeybee then moves on.