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: Humans are well-equipped for life on Earth. But in space, it is different. Low or _ changes how the blood flows and causes motion sickness, muscle loss and tiredness. Weightlessness can also cause bone loss. But scientists are experimenting with little worms to better understand how space travel affects astronauts. The millimeter-long worm is called C. elegans. The see-through worm is often used in medical studies because its life is only about two weeks long. Seventy percent of its DNA is the same as human DNA. Sabanayagam is a scientist, who built a micro-gravity simulator to test how C. elegans would perform in the actual zero gravity of space. Scientists put the worms into the simiulator full of water. After a week they take out the worms. They look for changes in the worms' epigenome,which are chemical markers that tell the DNA in the cells how to perform. The epigenome can be changed by the environment. And those changes pass from one generation of worms to the next. "When the worms are in a liquid environment, some epigenomic marks remain even when we take the animal out of the liquid environment and put it back into normal ground conditions. So its offspring keeps this epigenomic memory of the parents' liquid environment or microgravity environment." The information the scientists have gathered suggests that the epigenomic marks appear during the early part of a worm's life. Mr. Sabanayagam says he thinks scientists can find genes in the human similar to those in the worms that responded to microgravity and scientists could possibly observe those genes closely when astronauts travel in space. Sabanayagam expects C. elegans to visit the International Space Station within two years. He says he hopes information gathered from the worm studies can be used to develop simple, low-cost and quick tests to measure an astronaut's health.
Answer: has a short life period

A: From the passage we can know C. elegans _ .
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Q: Article: Dr charlotte Uhlenbroek recently returned to London after filming her second series, Jungle. It was difficult, 19-week trip, during which she explored the rainforests of Borneo, the Amazon and Congo, travelling around using variety of means of transport, including hot-air balloons and canoes. "I'm interested in the way animals communicate with each other. It was sometimes dangerous making the program ---I even went swimming with piranha fish. But the worst thing was insects. On one occasion I had 70 sand-fly bites on my arm. Luckily I didn't get sick. I prefer not to take tablets every day, but if I get a fever, take some medicine immediately." Filming the series was exciting, but also frightening at times. Her most challenging experience was climbing a 100-meter tree in Borneo, as she has a great fear of heights. "I had to keep pulling myself further and further upwards. All I wanted to do was get down again. Suddenly the safety equipment didn't look very strong and I thought that my ropes would break and I would crash to the ground." What did she enjoy most about returning to London? "When I've been away in hot uncomfortable conditions for a long time I dream about an ice-cold drink and my bed at home! But the thing I look forward to the most is nice long showers. There wasn't much water in some of the places we visited and I worried that I was using it all up and not leaving any for my colleagues on the camera team! "
Answer: she hates being in high places

A: Charlotte found climbing the tree in Borneo so frightening because _ .
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Q: Article: This summer, Monika Lutz's life took an unusual turn. Instead of heading off to college, the high school graduate packed her bags for a Bengali jungle. Lutz, like a growing number of other young Americans, is taking a year off. Gap years are quite common in Britain and Australia, but they are just beginning to catch on in the U.S. Lutz, who grew up in Boulder, Colo., has put together a 14-month schedule that includes helping deliver solar power to some communities in India and interning for a fashion designer in Shanghai---experiences that are worlds away from the lecture halls and university dormitories that await other students. "I could not be happier," she says. Why are students attracted to the gap-year concept? According to new survey data from Karl Haigler and Rae Nelson, education-policy experts and co-authors of The Gap-Year Advantage, the most common reason for this is to avoid burnout. "I felt like I was focused on college as a means to an end," says Kelsi Morgan, an incoming Middlebury College freshman who spent last year interning for a judge in Tulsa, Okla., and teaching English at an orphanage in the Dominican Republic. The hope is that after a year out of the classroom, students will enter college more energized, focused and mature. That can be an advantage for colleges too. Robert Clagett, dean of admissions at Middlebury, did some research a few years ago and found that a single gap semester was the strongest predictor of academic success at his school. Most experts recommend securing a spot in college before taking a gap year and warn against using the time off to lengthen your resume. "Most admissions folks can see right through that," says Jim Jump, the academic dean of St. Christopher's School in Richmond, Va. But for students like Lutz, who, after getting rejected from five Ivies, decided to take time off, a gap year can help focus interests. Lutz now plans to apply mostly to non-Ivies that have strong marketing programs. "This experience has really opened my eyes to the opportunities the world has to offer," she says. But at least one education expert doesn't want schools spreading the gap-year message. In a study that followed 11,000 members of the high school class of 1992 for eight years after graduation, Stefanie DeLuca, a sociology professor at Johns Hopkins University, found that, all things being equal, those who delayed college by a year were 64% less likely to complete a bachelor's degree than those who didn't. DeLuca did not say whether these students voluntarily started college late, but at the very least, her work indicates that taking a gap year doesn't guarantee success. "I'm not going to say that time off does not have benefits," says DeLuca. "But I think we should not be so enthusiastic."
Answer: they want to refresh themselves

A:
The students take gap years mainly because _ .
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