Classification Question

On this page, we will learn about: What is a classification question?, an example of a classification question, strategies to answer the classification questions, the IELTS Classification Question Practice Exercise: Why do we sleep?, and answers and explanations.

What is Classification Question?

In classification questions, you may be asked to categorize information from the reading text. You have some statements from the text and a list of options (listed as A, B, C, etc.). Your goal is to match each statement with the correct option.
Answers here do not necessarily appear in the order of the passage. You may use each option multiple times.

classification questions


Example of Classification Question:

classification questions

Strategies to answer the classification questions:

  1. Look at the given options (A, B, C, D or more than).
  2. Skim the text to get its general idea and see where each option is discussed. It may be helpful to underline the options in the text so it will be easier to find them later.
  3. Attentively read all the information that relates to the options.
  4. Read the statements carefully. If the statement relates to what you have just read, then classify it as per the given options. You may use scanning to identify the key words from the statement in the text.
  5. Steps 3 and 4 can be repeated with other options.

IELTS Classification Question Practice Exercise:

To understand the Classification Question better, let’s look at the following example: read the text and answer the questions below.
Questions 1-7

Classify the following statements as referring to
A. Matthew Walker
B. Ravi Allada
C. Paul-Antoine Libourel

Write the appropriate letters A, B or C in boxes 1-7:

  1. There are three major sleep-related behavioral characteristics.
  2. The notion that we sleep because we have nothing else to do is ludicrous.
  3. At some point throughout evolution, a new stage of sleep appeared: rapid eye movement(REM) sleep.
  4. Natural selection did not suppress sleep, but enhance it.
  5. Sleep makes animals’ react slowly.
  6. Every major system in a human's body is affected by lack of sleep. 
  7. Muscles are rarely active during sleep.

Let’s take a closer look at the strategy for answering the questions:

Firstly, you look through the given options and skim over the text. You have given 3 options on which you should focus:

  • Matthew Walker
  • Ravi Allada
  • Paul-Antoine Libourel

After you’ve skimmed over the text, it’s a good idea to"divide" the text into 3 sections, each section relating to one option. We’ve colored information about Matthew Walker in blue,Ravi Allada in rose , and part about Paul-Antoine Libourel in yellow.

Now, read the first part and look through the list of statements.

Why do we sleep?


Researchers have discovered that sleep is beneficial to humans in many ways: it helps us store memories and keeps our social and emotional lives on track. However, we still do not really know how, why, or even exactly when sleep evolved.

"The cost of losing consciousness to survival is astronomical," says Matthew Walker at the University of California, Berkeley. Whatever functions sleep performs, they must be so fundamentally crucial that they far outweigh the obvious vulnerability associated with sleeping.

This means we may confidently dismiss one of the simplest theories of sleep: that we drift off simply because we have nothing better to do. This could be known as the indolence theory of sleep. Once an animal has eaten, seen off any rivals, and exhausted all potential mating opportunities, it effectively has an empty schedule, and losing consciousness effectively kills time for a few hours.

It is a fun notion, but assuming that a sleeping animal is substantially more likely to be caught and eaten than a waking animal, this hypothesis makes "zero sense," says Walker.

There is now an emerging consensus on the behavioral features that constitute sleep, and these aspects can be utilized to look for sleep in simple animals, says Ravi Allada at Northwestern University in Evanston, Illinois.

According to Allada , there are three main elements. First and foremost, sleep renders an animal quiet and still; muscles are not highly active during sleep. Second, sleep enables animals to respond more slowly. For example, if you make a loud noise near a sleeping animal, it will react more slowly than an awake animal. And finally, we can recognize sleep because it prevents animals from getting tired.

"I believe  that the behavioral traits used to characterize sleep reliable for detecting this behavior in animals... and for distinguishing sleep from ordinary rest," says Paul-Antoine Libourel of France's Lyon Neuroscience Research Center in France.

Sleep, according to Libourel, now appears to be an almost universal element of animal life. "This suggests that sleep is fundamental for the survival of species. Natural selection did not suppress it. In fact, natural selection did the exact opposite: it built on the concept of sleep, adding in new stages and new functions."

"At some point in prehistory, the most famous of all stages of sleep appeared: rapid eye movement (REM) sleep," explains Walker. "Non-REM sleep was the original form."

Every major system in the body is impacted by sleep. Cut down on sleep and it is not just your brain that struggles; the reproductive, metabolic, cardiovascular, thermoregulatory, and immune systems all suffer too, according to Libourel.

All the explanations for sleep we have examined ultimately boil down to the same thing: sleep is a state we enter to repair the systems that are put under stress when we are awake.

Answers & explanations:

A. After you’ve read the information related to Matthew Walker, look through the list of statements and see which ones match to what you have just read:

  1. There are three major sleep-related behavioral characteristics.
  2. The notion that we sleep because we have nothing else to do is ludicrous.
  3. At some point throughout evolution, a new stage of sleep appeared: rapid eye movement(REM) sleep.
  4. Natural selection did not suppress sleep, but enhance it.
  5. Sleep makes animals’ react slowly.
  6. Every major system in a human's body is affected by lack of sleep. 
  7. Muscles are rarely active during sleep.

We can clearly, sentences 2 and 3 belong to Matthew Walker. In the beginning of the text, he said:

"This means we may confidently dismiss one of the simplest theories of sleep: that we drift off simply because we have nothing better to do."

And at the end of the passage, there’s Walker’s saying:

"At some point in prehistory, the most famous of all stages of sleep appeared: rapid eye movement (REM) sleep"


B. Now you should carefully read Ravi Allada’s part and look through the rest of the statements. As the other statements are not referred to by Mr. Walker, we put letter A near statements 2 and 3 and move on to the next part.

  1. There are three major sleep-related behavioral characteristics.
  1. Natural selection did not suppress sleep, but enhance it.
  2. Sleep makes animals’ react slowly.
  3. Every major system in a human's body is affected by lack of sleep. 
  4. Muscles are rarely active during sleep.


Again, we can see from the text that Ravi Allada describes 3 behavioural features that describe sleep (statement 1). The first feature refers to statement 7:

" First and foremost, sleep renders an animal quiet and still; muscles are not highly active during sleep."

The second feature relates to statement 5:
" Second, sleep enables animals to respond more slowly."

1, 5, and 7 statements correspond to answer B.



C. Now, there are only 4 and 6 statements left. If you read the information referred to by Paul-Antoine Libourel, you will see that statements 4 and 6 correspond to answer C.