In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.

Let me give you an example: Article: Homework can put you in a badmood , and that might actually be a good thing. Researchers from the University of Plymouth in England doubted whether mood might affect the way kids learn. To find out the answer, they did two experiments with children. The first experiment tested 30 kids. Someshapes were hidden inside a different, larger picture. The kids had to find the small shapes while sitting in a room with either cheerful or sad music playing in the background. To test their mood, the scientists asked the kids to point to one of five faces, from happy to sad. Children who listened to cheerful music tended to point to the smiley faces while the others pointed to the unhappy ones. The researchers found that sad kids took at least a second less to find the small shapes. They also found an average of three or four more shapes. In the second experiment, 61 children watched one of two scenes from a film. One scene was happy, and the other was sad. Just like in the first experiment, kids who saw the sad scene acted better compared to the others. The researchers guessed that feeling down makes people more likely to focus on a problem or difficult situation. Not all scientists agree with them, however. Other studies argued that maybe, that cheerful music in the first experiment distracted kids from finding shapes. While scientists work on finding out the answers, it still might be wise to choose when to do your tasks according to your mood. After eating a delicious ice cream, for example, write an essay.
Answer: whether mood affects their learning ability
The answer to this example can be: Researchers did experiments on kids in order to find out _ .
Here is why: It is clearly mentioned in the article that to the check effect of mood on children is the main purpose of the experiment.

OK. solve this:
Article: Wake Up,Sleep Gene Some people can stay up all night and still get work done the next day.I'm not one of them.After a night without enough sleep,I feel bad-tempered.I have trouble remembering things.And all I want to do is crawl back into bed and sleep. How do you feel after you've stayed up late to finish schoolwork? Or the day after an overnight party? Scientists now say that your answers to these questions may depend on your genes. New research suggests that a gene called period 3 affects how well you function without sleep.The period 3 gene comes in two forms: short and long.Everyone has two copies of the gene.So,you may have two longs,two shorts,or one of each.Your particular combination depends on what your parents passed on to you. Scientists from the University of Surrey in England studied 24 people who had either two short or two long copies of period 3.Study participants had to stay awake for 40 hours straight.Then,they took tests that measured how quickly they pushed a button when number flashed on a screen and how well they could remember lists of numbers. Results showed that the people with the short form of period 3 performed much better on these tests than the people with the long form did.In both groups,people performed worst in the early morning.That's the time when truck drivers and other night-shift workers say they have the most trouble concentrating. After the first round of experiments,participants were finally allowed to sleep.People in the group that performed well on the tests took about 18 minutes to nod off. People with the long period 3 genes,by contrast,fell asleep in just 8 minutes.They also spent more time in dip sleep.That suggests that people with the long form of the gene need more and deeper sleep to keep their brains working at top form. I think I must have the long form of period 3.What about you?
Answer: to tell the result of a research on sleepy gene
Answer:
The purpose of this passage might be _ .