Question 148·Easy·Inferences
Recent studies suggest that migrating monarch butterflies rely on an internal compass that combines information from the Sun and their circadian (daily) rhythm. In one experiment, researchers kept monarchs indoors under artificial light that was shifted six hours ahead of the natural day–night cycle. When released outdoors, these butterflies began flying west rather than the usual southward direction seen in autumn migration. The researchers concluded that the insects had reset their internal clocks to match the shifted schedule. This result suggests that ______
Which choice most logically completes the text?
For inference-based text completions, restate the experiment as a cause-and-effect relationship (what changed, and what happened). Then eliminate choices that add new mechanisms, make absolute claims (“only,” “require,” “unable”), or reach beyond what was tested. Choose the option that directly reflects the observed relationship.
Hints
Focus on cause and effect
What did the researchers change, and what changed in the butterflies’ behavior afterward?
Connect the internal clock to direction
The butterflies reset their internal clocks to the shifted schedule, then flew the wrong direction under the real Sun. What does that imply about what the clock is used for?
Eliminate extremes and new ideas
Be cautious with choices that add new mechanisms not mentioned (like magnetic-field-only navigation) or use absolute words like “only” or “require.”
Step-by-step Explanation
Identify what the question is asking
The question asks what the experimental result "suggests"—that is, what inference is logically supported by the described setup and outcome, without adding new claims.
Summarize the key parts of the experiment
Key details:
- Monarchs normally migrate south in autumn.
- Researchers shifted the indoor light cycle by 6 hours.
- The butterflies reset their internal clocks to that shifted schedule.
- When released outdoors under the normal Sun, they flew west instead of south.
Infer what the result implies about navigation
Because changing the butterflies’ internal timing (while the outdoor Sun remained on the normal schedule) changed their flight direction, their directional flight must depend on how their circadian timing aligns with the Sun.
Match this inference to the answer choices
Eliminate choices that introduce unsupported requirements (artificial lighting), new mechanisms (magnetic-field-only navigation), or claims about an untested group (butterflies kept outdoors). The supported inference is “monarch butterflies’ flight direction depends on their circadian clock being aligned with the Sun.”