Question 160·Easy·Central Ideas and Details
For a recent study, scientists investigating monarch butterfly migration patterns noticed that in years with unusually warm spring temperatures, the butterflies began traveling north almost two weeks earlier than normal. To confirm this observation, the scientists consulted four decades of sighting logs maintained by volunteer naturalists and compared the date of the season’s first recorded butterfly in each log with temperature records from nearby weather stations.
According to the text, how did the scientists verify that monarch butterflies were starting their migration sooner than usual?
For “According to the text” detail questions, underline the key task word (here, “verify” or “confirm”) and then scan the passage for that exact idea or phrase. Once you find the relevant sentence, restate it in your own words and then pick the answer that best paraphrases that information without adding new details. Quickly eliminate choices that introduce methods, tools, or concepts that never appear in the passage, even if they sound scientifically plausible.
Hints
Find the part of the passage about checking their observation
Scan for where the passage shifts from describing what the scientists noticed to how they confirmed or verified that notice. Look especially for a transition phrase like “To confirm this observation.”
Focus on the specific actions the scientists took
In the sentence after that transition, identify exactly what sources of information the scientists used and what they did with those sources.
Eliminate choices that add new, unmentioned methods
Ask yourself: Do the scientists ever mention using a lab, tracking devices, or DNA/genes? Remove any choices that describe techniques not found anywhere in the passage.
Step-by-step Explanation
Understand what the question is asking
The question asks: “How did the scientists verify that monarch butterflies were starting their migration sooner than usual?” This means you must find what specific method or action the scientists used to confirm their initial observation.
Locate the key sentence in the passage
Look for wording in the passage that signals confirmation or verification. The sentence starting with “To confirm this observation, the scientists…” is crucial, because it directly answers how they checked their idea.
Paraphrase the scientists’ method from the text
Read that key sentence carefully:
- They consulted four decades of sighting logs kept by volunteer naturalists.
- They compared the date of the season’s first recorded butterfly in each log
- With temperature records from nearby weather stations. Put simply, they used long-term volunteer records of first sightings and matched those dates with temperature data.
Match the paraphrase to the correct answer choice
Now compare your paraphrase to the options:
- Choices about laboratory experiments, satellite tags, or genetic adaptations never appear in the passage.
- The only option that matches the described method of using long-term sighting logs and weather data is: “They compared decades of volunteer sighting records with temperature data.”