Question 13·Easy·Central Ideas and Details
A recent study compared summertime temperatures across several metropolitan neighborhoods and found that areas with abundant tree canopy were on average 5°F cooler than those with few trees. The researchers attribute the temperature difference to the shade and moisture that trees provide and conclude that expanding urban forests is one of the most effective strategies cities can use to combat rising heat.
Which choice best states the central idea of the passage?
For central idea questions, first quickly paraphrase the passage in your own words in one short sentence—focus on who or what the passage is mainly about and what is claimed about them. Then scan the answer choices and eliminate any that (1) introduce new topics not mentioned in the passage, (2) focus on minor details rather than the overall finding or conclusion, or (3) contradict the passage’s main message. Finally, choose the option that best matches your paraphrase and includes both the key evidence and the author’s or researchers’ main conclusion when possible.
Hints
Locate the study’s key result
Focus on the sentence that gives the numerical result (the 5°F difference) and think about what that result shows overall.
Notice the researchers’ conclusion
Look closely at the final sentence starting with “The researchers attribute…” and “conclude that…”. What do they say cities should do, and why?
Check for both evidence and recommendation
The best answer should reflect both what the study found about temperatures and the action the researchers say cities should take based on that finding.
Watch out for off-topic choices
Eliminate choices that focus on issues the passage does not discuss, such as public health concerns, traffic, or measurement difficulties.
Step-by-step Explanation
Identify what the question is asking
The question asks for the central idea of the passage. That means you need the answer choice that summarizes the main point of the whole paragraph, not a side detail or a new idea.
Summarize the passage in your own words
Restate the passage briefly:
- A study compares temperatures in different city neighborhoods.
- It finds that areas with many trees are about 5°F cooler than areas with few trees.
- Researchers say this is because of the shade and moisture trees provide.
- They conclude that expanding urban forests is one of the best ways for cities to fight increasing heat.
The passage is mainly about what trees do for temperatures and what cities should do about it.
Match answer choices to the passage’s main focus
Now compare each option to your summary:
- Ask: Does this option mention both trees (tree canopy) and their effect on temperature / heat?
- Also ask: Does it reflect the conclusion that cities should act based on this effect?
Eliminate any choice that:
- Brings up causes the passage never mentions (like traffic, building materials),
- Focuses on public health or residents’ feelings rather than the tree-temperature relationship,
- Emphasizes difficulties measuring effects instead of the clear result and recommendation.
Choose the answer that states the study’s finding and conclusion
The only choice that clearly states that tree canopy significantly cools neighborhoods and that planting more trees can help cities reduce summer heat is: “Planting more trees can help cities reduce summer heat because tree canopy significantly lowers neighborhood temperatures.”