Question 88·Medium·Central Ideas and Details
Entomologist Sylvia Romero and her team recently surveyed populations of wild bumblebees in 25 North American cities. They found that colonies nesting in city parks had genetic markers indicating recent interbreeding among formerly isolated lineages, and the bees’ foraging patterns had shifted toward earlier morning activity compared with rural colonies. Because these shifts were found consistently across all cities studied, Romero argues that urban bumblebees are evolving a common "city ecotype" that helps them cope with higher temperatures and fragmented food sources characteristic of metropolitan areas.
Which choice best states the main idea of the text?
For main-idea questions, first read the passage with the goal of finding the author’s overall point, not every detail. After reading, briefly restate the main idea in your own words, then compare that summary to each answer choice and eliminate choices that (1) bring in new or exaggerated information, (2) focus on a single detail instead of the overall point, or (3) contradict the tone or conclusion of the passage. Usually, the main idea is expressed or strongly implied in the first or last sentence, so give those special attention to work quickly and accurately.
Hints
Find the thesis sentence
Look especially at the last sentence of the passage. Authors often put their main conclusion or argument there.
Separate main idea from details
Ask yourself: What is Romero arguing overall about urban bumblebees, not just what specific measurements or observations she reports?
Watch for extreme or new information
Be careful with choices that mention things not in the passage (like new species) or that sound much more negative or narrow than the text’s overall description.
Check if the choice covers both evidence and conclusion
The best answer should reflect that the researchers observed consistent changes and used those changes to support a broader claim about urban bumblebees.
Step-by-step Explanation
Identify the task
The question asks for the main idea of the text. That means you need the overall conclusion or point of the passage, not a small detail.
Locate the author’s conclusion
Look at the end of the passage, where authors often state their main point:
"Because these shifts were found consistently across all cities studied, Romero argues that urban bumblebees are evolving a common 'city ecotype' that helps them cope with higher temperatures and fragmented food sources characteristic of metropolitan areas."
This sentence gives Romero’s argument: urban bumblebees are evolving a common city ecotype to cope with city conditions.
Summarize the key components
Break that conclusion into simpler parts:
- There are consistent shifts (genetic markers and earlier foraging times).
- These shifts appear across many cities.
- Romero argues this means bumblebees are evolving a shared form.
- This shared form helps them adapt to urban conditions (higher temperatures and fragmented food sources).
The main idea should include both the consistent changes and the adaptation to city environments.
Compare each answer to the summarized main idea
Now check which option matches that summary:
- Eliminate choices that mention things the passage never says (like mixing with honeybees or species endangerment).
- Eliminate choices that focus on only one detail (like just foraging times) instead of the overall conclusion.
The remaining choice should match the idea that consistent genetic and behavioral changes in city bumblebees suggest they are developing a shared form adapted to urban environments. That is exactly what choice B states.