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: There can be no doubt about the positive changes that have taken place in the last hundred yeas. In Western countries we eat more nutritiously, we are wealthier, we are healthier and there are more opportunities. But then, why, in the midst of so much excitement and opportunity, has life satisfaction declined so much? Why is depression the most common illness in the Western world? And why, when most infectious diseases have been conquered and rates of heart attacks and stokes have been reduced, do so many people report that they are feeling ill? It is argued that "functional illnesses" such as constant tiredness, the inability to sleep and anxiety that makes you ill, are caused by the body's failure to adapt to social change. Modern life is exhausting because we are often compelled to live by its standards, even though technically we have a choice to live otherwise. Everybody thought we would benefit from the invention of machines to carry out the more dull tasks in our life, leaving us many more opportunities for leisure and relaxation. And yet the opposite has happened. Only recently a lifestyle survey found that for 42% of its 5,000 interviewees, lack of sleep was their principal health concern, followed by 34% worrying about general exhaustion. A quarter acknowledged experiencing stress and depression. Working long hours in companies with a restricted social life is threatening our health and people feel unable to cope. The new technological age that claims freedom by allowing us greater flexibility is, in fact, slowly working to destroy us. Jobs for the whole life are an old story. If people take time out to recover, somebody else will come along to fill their position. Who, in this current every-man-for-himself climate, wants their employer to think they cannot cope, especially when there are mortgages and families at stake?
Answer: infectious diseases have declined
Answer:
Over the last century, in Western countries _ .