What Citizen Science Can and Cannot Show
About this practice test
An explanation of how citizen science supports environmental monitoring, what patterns it can reveal, and why other evidence is needed for exact totals and causes.
What you’ll practice
Finding detail
Locate specific information and evidence.
Interpreting ideas
Connect main points and inferences.
Evaluating arguments
Assess claims, evidence, and limitations.
What to expect:
8 questions with explanations to review after submission.
Study the questions and tasks
Work through the material below, or start the interactive practice above to complete an attempt. Try the exercises before opening any answer or transcript sections, then use them to review your work.
- Practice level
- B2. Try this level if you can follow the instructions and understand most of the language; choose an earlier level if you need more support.
- Question formats
- Multiple choice
How to approach this practice
Read the passage for its main idea, then return to the relevant sentence or paragraph for each question. Base answers on the passage.
What Citizen Science Can and Cannot Show
Citizen science asks ordinary people to collect observations that help answer environmental questions. A walker can photograph a bird, a gardener can note the first frogs of spring, and a cyclist can upload a picture of polluted water. The appeal is obvious: many observers can cover a wide area at the same time, and they can do it repeatedly. But the same openness that makes the approach powerful also means the results need careful reading. Its greatest strength is not precision but reach. If hundreds of people report starlings at once, researchers can see a migration wave or a sudden local peak. They can also notice that a species appears earlier in some years than in others. What they cannot do from such reports alone is count every bird or prove why the pattern changed. A large number of sightings may suggest that something is happening; it does not, by itself, explain the cause. The method is especially useful when speed matters. On one coast, beach visitors uploaded photos of foamy water and a reddish tide within hours. Because the reports arrived quickly and from several points along the shore, local officers could check the area before the bloom spread further. Yet the images did not tell them whether the bloom began with warm weather, fertilizer runoff, or a change in currents. Citizen science can alert people early, but an alert is not the same as a diagnosis. The main danger is bias. Volunteers do not sample the world evenly. They are more likely to notice rare or striking species, to walk in parks and beaches rather than private land, and to record observations on sunny weekends when they themselves are outside. A map built from such data can be very informative, but empty spaces on the map may simply mean nobody looked there. For that reason, apps often ask users to attach a photo and a location, and trained reviewers may check unusual records. To answer questions about causes, scientists usually combine citizen data with other evidence. In one valley, volunteers mapped ponds where frogs had vanished. Professional teams then measured water quality, and local farmers described changes in drainage. Only when these lines of evidence were compared did the cause become visible. Citizen reports showed where the decline was happening; the extra work explained why. That is the pattern again and again: citizen science is strongest at describing distribution, timing, and unexpected events, but weaker at proving mechanism. So citizen science should not be praised as a magic substitute for research, nor dismissed as amateur noise. It is a method with a clear place. Used well, it broadens what scientists can see and involves the public in environmental noticing. Used badly, it produces confident-looking maps that hide uncertainty. The best questions are the ones that match the method: where is something happening, when does it appear, and how quickly is it changing? For exact totals or causes, the answer usually needs other tools too.
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Question 1 · Multiple choice
Choose all the correct answers.
According to the writer, which TWO ideas describe the main value of citizen science? Choose TWO answers.
Return to the passage, recording or visual- It always gives a complete count of every species.
- It can show broad patterns across a large area.
- It can prove the exact reason a change happened.
- It can be done by many people at the same time.
Check answers and explanations
- Answer
- It can show broad patterns across a large area.; It can be done by many people at the same time.
The passage says citizen science is strongest for reach and broad patterns, not exact totals. The correct choices are the ones that match this: it can show broad patterns across a large area and it can be done by many people at the same time. The other options are rejected because the writer explicitly says it cannot count every bird or prove the cause on its own.
Its greatest strength is not precision but reach
many observers can cover a wide area at the same time
It always gives a complete count of every species.: Not supported: the writer says it cannot count every bird from reports alone.
It can show broad patterns across a large area.: Supported: the writer says citizen science is strong in reach and pattern-spotting.
It can prove the exact reason a change happened.: Not supported: the passage says reports alone cannot prove why the pattern changed.
It can be done by many people at the same time.: Supported: the writer emphasizes many observers working together over a wide area.
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Question 2 · Multiple choice
Choose all the correct answers.
According to the writer, which TWO features can make raw citizen reports biased? Choose TWO answers.
Return to the passage, recording or visual- They are more likely to notice rare or striking species.
- All records from sunny days are rejected.
- They often work in parks and beaches rather than private land.
- Volunteers are assigned evenly across all habitats.
Check answers and explanations
- Answer
- They are more likely to notice rare or striking species.; They often work in parks and beaches rather than private land.
The passage explains that volunteers do not sample evenly and tend to notice certain places and species more than others. The correct answers reflect that people focus on parks and beaches rather than private land, and that they are more likely to notice rare or striking species. The other choices are wrong because the passage does not say records are automatically discarded, and it does not claim volunteers are assigned evenly across all habitats.
They are more likely to notice rare or striking species, to walk in parks and beaches rather than private land
and to record observations on sunny weekends when they themselves are outside
They are more likely to notice rare or striking species.: Supported: the writer names this as a source of bias.
All records from sunny days are rejected.: Not supported: sunny weekends are mentioned as a bias in who records, not as a reason to reject data.
They often work in parks and beaches rather than private land.: Supported: the passage says volunteers tend to observe in these easier places.
Volunteers are assigned evenly across all habitats.: Not supported: the passage says volunteers do not sample the world evenly.
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Question 3 · Multiple choice
Choose all the correct answers.
In the coastal example, which TWO things happened? Choose TWO answers.
Return to the passage, recording or visual- The reports proved fertilizer runoff was the cause.
- People uploaded photos of foamy water and a reddish tide.
- The bloom was shown to be harmless.
- Officers could check the area sooner.
Check answers and explanations
- Answer
- People uploaded photos of foamy water and a reddish tide.; Officers could check the area sooner.
The passage describes two things that actually happened in the coastal case: beach visitors uploaded photos of foamy water and a reddish tide, and the quick reports allowed local officers to check the area before the bloom spread further. The other options are wrong because the passage does not say the bloom was harmless or that the cause had already been proven.
beach visitors uploaded photos of foamy water and a reddish tide within hours
local officers could check the area before the bloom spread further
The reports proved fertilizer runoff was the cause.: Not supported: the passage says the images did not tell them the cause.
People uploaded photos of foamy water and a reddish tide.: Supported: this is exactly what the passage says happened in the coastal example.
The bloom was shown to be harmless.: Not supported: the passage gives no such conclusion.
Officers could check the area sooner.: Supported: the reports arrived quickly enough to trigger an early check.
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Question 4 · Multiple choice
Choose all the correct answers.
Which TWO conclusions can researchers draw from the starling reports? Choose TWO answers.
Return to the passage, recording or visual- The species has stopped breeding everywhere.
- A migration wave may be under way.
- A sudden local peak may be visible.
- The exact number of birds in the region is known.
Check answers and explanations
- Answer
- A migration wave may be under way.; A sudden local peak may be visible.
The writer says that many simultaneous starling reports can reveal a migration wave or a sudden local peak. The passage also states what cannot be concluded: the exact total number of birds or the cause of the pattern. Therefore the supported answers are the ones about a migration wave and a local peak.
researchers can see a migration wave or a sudden local peak
What they cannot do from such reports alone is count every bird or prove why the pattern changed
The species has stopped breeding everywhere.: Not supported: this idea is never claimed in the passage.
A migration wave may be under way.: Supported: the passage gives this as a possible conclusion from many reports.
A sudden local peak may be visible.: Supported: the passage names this as another thing researchers can see.
The exact number of birds in the region is known.: Not supported: the writer says reports alone cannot count every bird.
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Question 5 · Multiple choice
Choose all the correct answers.
Which TWO actions does the writer say help make citizen data more trustworthy? Choose TWO answers.
Return to the passage, recording or visual- Removing inexperienced volunteers from the project.
- Having trained reviewers check unusual records.
- Letting users report without any details.
- Asking for a photo and a location.
Check answers and explanations
- Answer
- Having trained reviewers check unusual records.; Asking for a photo and a location.
The writer points to two safeguards: asking users to attach a photo and a location, and having trained reviewers check unusual records. The wrong options go beyond the passage or contradict it, because the writer does not say that all inexperienced volunteers should be removed or that no details should be given.
apps often ask users to attach a photo and a location
trained reviewers may check unusual records
Removing inexperienced volunteers from the project.: Not supported: the passage never suggests excluding inexperienced people.
Having trained reviewers check unusual records.: Supported: the passage explicitly mentions trained reviewers.
Letting users report without any details.: Not supported: the writer presents the opposite approach as helpful.
Asking for a photo and a location.: Supported: the passage says these details are often requested.
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Question 6 · Multiple choice
Choose all the correct answers.
Which TWO things does the writer say citizen science cannot do on its own? Choose TWO answers.
Return to the passage, recording or visual- Explain why a species is declining.
- Show where a decline is happening.
- Count every bird in an area.
- Record unexpected events.
Check answers and explanations
- Answer
- Explain why a species is declining.; Count every bird in an area.
Citizen science can show where a problem is happening, but it cannot by itself explain the cause or provide exact totals. The writer says those tasks need other evidence or other tools. So the correct answers are the ones about explaining decline and counting every bird.
What they cannot do from such reports alone is count every bird or prove why the pattern changed
For exact totals or causes, the answer usually needs other tools too
Explain why a species is declining.: Supported: the passage says citizen reports alone cannot prove why a change happened.
Show where a decline is happening.: Not supported: the passage says citizen reports can show where the decline is happening.
Count every bird in an area.: Supported: the writer states that reports alone cannot count every bird.
Record unexpected events.: Not supported: the passage says citizen science is strong at unexpected events.
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Question 7 · Multiple choice
Choose all the correct answers.
Which TWO wider benefits of citizen science are mentioned by the writer? Choose TWO answers.
Return to the passage, recording or visual- It only works for rare species.
- It removes the need for professional surveys.
- It involves the public in environmental noticing.
- It broadens what scientists can see.
Check answers and explanations
- Answer
- It involves the public in environmental noticing.; It broadens what scientists can see.
The final paragraph says citizen science broadens what scientists can see and involves the public in environmental noticing. These are its wider benefits. It does not replace professional surveys, and it is not mainly about giving exact totals, so those choices are wrong.
it broadens what scientists can see and involves the public in environmental noticing
It is a method with a clear place
It only works for rare species.: Not supported: the passage discusses many kinds of environmental observations, not only rare species.
It removes the need for professional surveys.: Not supported: the passage says other tools are still needed for exact totals or causes.
It involves the public in environmental noticing.: Supported: this is named directly as a benefit.
It broadens what scientists can see.: Supported: the writer states this directly in the conclusion.
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Question 8 · Multiple choice
Choose all the correct answers.
Which TWO statements best match the writer's final view? Choose TWO answers.
Return to the passage, recording or visual- Citizen science is mainly useful because it gives exact totals.
- Other tools are still needed for exact totals or causes.
- Citizen science works best when the question suits the method.
- Citizen science should be dismissed as amateur noise.
Check answers and explanations
- Answer
- Other tools are still needed for exact totals or causes.; Citizen science works best when the question suits the method.
The writer ends by saying that the best questions are the ones that match the method, and that exact totals or causes usually need other tools. Those are the two supported views. The other options misrepresent the conclusion: citizen science is not praised mainly for exact totals, and it is not dismissed as useless.
The best questions are the ones that match the method
For exact totals or causes, the answer usually needs other tools too
Citizen science is mainly useful because it gives exact totals.: Not supported: the writer says precision is not its greatest strength.
Other tools are still needed for exact totals or causes.: Supported: the passage says this directly in the conclusion.
Citizen science works best when the question suits the method.: Supported: this is the writer's closing judgment.
Citizen science should be dismissed as amateur noise.: Not supported: the writer rejects this dismissal and gives the method a clear place.
What to review next
Find the words that support each answer. For a mistake, compare the question with the evidence and identify the detail or inference you missed.
A focused practice result shows how you did on these tasks. Use several activities across skills to decide what to study next; one practice score does not certify an overall CEFR level.
Before you practise: a worked example
Look for evidence in the text. Separate what the writer says from what you already know about the topic.
The library normally closes at six, but on Fridays it stays open until eight. When does it close on Friday?
The answer is eight. But introduces an exception to the normal closing time, so the first time mentioned is not the answer.
This teaching example is separate from the scored questions. After your test, compare any mistakes with the explanation and revisit the topic before trying again.