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.

Q: Article: We all enjoy the colors of autumn leaves. Did you ever wonder how and why a fall leaf changes color? Where do the yellows and oranges come from? To answer those questions, we first have to understand what leaves are and what they do. Leaves are nature's food factories. Plants take water from the ground through their roots. They take a gas called carbon dioxide from the air. Plants use sunlight to turn water and carbon dioxide into glucose, which is a kind of sugar. Plants use glucose as food for energy and as a building block for growing. The way plants turn water and carbon dioxide into sugar is called photosynthesis, which means " putting together with light. " A chemical called chlorophyll helps make photosynthesis happen. Chlorophyll is what gives plants their green color. As summer ends and autumn comes, the days get shorter and shorter. This is how the trees "know" to begin getting ready for winter. During winter, there is not enough light or water for photosynthesis. The trees will rest, and live off the food they stored during summer. They begin to shut down their food-making factories. The green chlorophyll disappears from the leaves. As the bright green fades away, we begin to see yellow and orange colors. Small a-mounts of these colors have been in the leaves all along. Covered up by the green chlorophyll, we just can't see them in summer. The bright reds and purples we see in leaves are made mostly in the fall. In some trees, like maples, glucose is trapped in the leaves after photosynthesis stops. Sunlight and the cool nights of autumn cause the leaves turn this glucose into a red color. The brown color of trees like oaks is made from wastes left in the leaves. It is the combination of all these things that make the beautiful colors we enjoy in the fall.
Answer: introduce the topic of the passage

A: The writer asked two questions in the beginning in order to_.
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Q: Article: It is common for older people to forget things. Now an American study has found that memory starts to fail when we are young adults. People younger than thirty years of age usually do not know that they are starting to forget information. But scientists from the University of Michigan say the loss of memory has usually already started. Researchers say people do not observe this slow reduction in mental ability until the loss affects their everyday activities. Denise Park led the new study. She directs the Centre for Aging and Cognition at the Institute for Social Research at the University of Michigan. Her team studied more than 350 men and women between the ages of twenty and ninety years. The study identified people in their middle twenties with memory problems. She says young adults do not know they are forgetting things because their brains have more information than they need. But she says that people in their twenties and thirties are losing memory at the same rate as people in their sixties and seventies. Ms. Park says people between the ages of sixty and seventy may note the decrease in their mental abilities. They begin to observe that they are having more trouble remembering and learning new information. The study found that older adults are more likely to remember false information as being true. For example, they remembered false medical claims as being true. Younger people remembered hearing the information. But they were more likely to remember that it was false. Ms. Park is now using modern imaging equipment to study what happens in the brains of people of different ages. She is studying what parts of the brain older adults use for different activities compared to younger adults. Ms. Park says mental performance is a direct result of brain activity and brain structure. She says keeping the brain active is important. She hopes future studies will identify ways to improve the operation of our aging minds.
Answer: introduce effective ways to improve memory

A: The passage is meant to _ .
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Q: Article: In my opinion, there is only one legitimate handgun sport and that is aim practice. It is practiced at objects which are properly monitored and usually quite safe. Only certain handguns are true "sporting weapons", seen as such by the sport's lovers. On the other hand, shooting at tin cans and other small objects in one's backyard is not and should not be considered a serious sport. When uncontrolled, it can be a very dangerous practice. Some opponents of handgun control have stated that we are out to stop all hunting and that controlling the handgun would severely affect hunting. That is simply untrue. Handgun control would in no way limit the freedom of the true hunter. Few if any hunters consider the handgun an effective hunting weapon. There are a few hunters who do hunt with handguns, but most states place restrictions on the type of guns that can be used in hunting, the reason is that killing of game should be done in as humane a way as possible. Some small handguns are more likely to wound the animal rather than kill it at once. Only long guns, rifles and shotguns are effective arms of hunting. People must understand that handguns and hunters are separate matters. Because most of the hunters use a rifle or shotgun, there is no reason why their search for game and sport should be affected by handgun control. Mixing the anti-hunting matter with the handgun matter confuses the killing of animals with killing of people.
Answer: objects are only small tin cans in the backyard

A:
In the writer's opinion, people should use handguns only when _ .
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