Question 95·Medium·Command of Evidence
In an environmental science essay, a student claims that chronic noise pollution in cities reduces the foraging efficiency of urban bat populations.
Which finding, if true, would most directly support the student’s claim?
For "Which finding best supports the claim?" questions, first underline the core claim (who/what is affected, by what cause, and in what way). Translate any technical phrase (like "foraging efficiency") into simple, measurable outcomes (time, success rate, amount). Then scan the choices for one that directly links the same cause and same outcome in a cause-and-effect way—experimental comparisons (A vs. B conditions) are especially strong. Quickly eliminate options that only give background facts, correlations without showing the effect on the outcome, or that ignore either the cause or the specific result stated in the claim.
Hints
Clarify the claim
Restate the claim in your own words: what exactly is supposed to happen to urban bats when there is chronic noise pollution?
Focus on the key outcome
Ask yourself: which answer talks specifically about how well or how quickly bats find and catch food, not just where they live or what environments are like?
Look for cause-and-effect
Which option suggests that noise itself leads to a measurable change in bats’ foraging performance, rather than just describing background facts about cities or bat species?
Prefer experimental evidence
See if any choice describes a controlled experiment comparing bats in noisy vs. quiet conditions, because that kind of evidence most directly tests the claim.
Step-by-step Explanation
Understand the claim you must support
The student claims that chronic noise pollution in cities reduces the foraging efficiency of urban bats.
In simpler terms:
- There is noise (cause).
- It affects urban bats.
- It makes them less efficient at finding and catching food (foraging).
So the supporting finding must connect city noise directly to bats being slower or less successful at catching prey.
Translate "foraging efficiency" into testable results
"Foraging efficiency" is about how effectively bats get food. A reduction in efficiency could look like:
- Taking longer to find and catch prey.
- Catching fewer insects in the same amount of time.
- Needing more effort or time to get the same amount of food.
The strongest evidence will show that when noise is present, one of these measurable outcomes gets worse.
Look for a direct comparison of noisy vs. quiet conditions
The most direct support usually comes from a controlled comparison:
- Bats in noisy conditions vs. bats in quiet conditions.
- A clear measurement of how long they take or how many insects they catch.
Now scan the answer choices for one that:
- Mentions noise levels.
- Describes bats’ success at catching prey.
- Shows a difference between noisy and quiet conditions.
Eliminate choices that don’t show noise reducing efficiency
Check each option against what you need:
- One option only says noisy areas also have more streetlights and insects (this doesn’t show bats doing worse).
- One option is about rural vs. urban species’ echolocation frequencies, not about noise making urban bats less efficient.
- One option talks about where urban bats roost (buildings and bridges), not about feeding or noise.
These do not directly show that noise causes worse foraging performance, so they can be eliminated.
Choose the finding that shows a causal effect of noise on feeding success
The remaining option describes a controlled experiment where:
- Urban bats are exposed to traffic-noise recordings.
- They are compared to bats in silence.
- The noisy group takes about 30% longer to locate and capture insect prey.
This directly shows that noise pollution causes urban bats to be slower at catching prey, meaning their foraging efficiency is reduced, so the correct answer is:
In a controlled experiment, urban bats exposed to traffic-noise recordings took about 30% longer to locate and capture insect prey than bats in silence.