根据短文内容，从下框的A—F选项中选出能概括每一段主题的最佳选项，并在答题卡上将该选项涂黑，选项中有一项为多余项。

    Research shows that pets help reduce stress．Do you know why and how?

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    For those who love animals,  it's virtually impossible to stay in a bad mood when a pair of loving puppy eyes meets yours, or when a super - soft cat rubs up against your head． Research supports the mood - enhancing benefits of pets．A recent study found that men with AIDS were less likely to suffer from depression if they owned a pet． According to a study, men with AIDS who had pets were only about 50 percent more likely to report symptoms of depression, compared to men with (AIDS who didn't have pets．）

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    While ACE inhibiting drugs can generally reduce blood pressure, they aren't as effective on controlling spikes in blood pressure due to stress and tension．However, in a recent study, a group of patients who got dogs or cats were found to have lower blood pressure and haut rates than those having no pets．When they heard of the results, most of those in the non - pet group went out and got pets !

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    Whether we walk our dogs because they need it, or are more likely to enjoy a walk when we have companionship, dog owners do spend more time walking than non - pet owners, at least if we live in an urban setting．Because exercise is good for stress management and overall health, owning a dog can be credited with increasing these benefits．

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    When we're out walking, having a dog with us can make us more approachable and pave people a reason to stop and talk, thereby increasing the number of people we meet, giving us an pop corduroy to increase our net - work of friends and acquaintances, which also has great stress management benefits．

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    Peels can be there for you in ways that people can't．They can offer love and companionship, and can also enjoy comfortable silence, keep secrets and are excellent companions．And they could be the best killer to loneliness．In fact, research shows that nursing home residents reported less loneliness when visited by dogs than when they spent time with other people !  All these benefits can reduce the amount of stress people experience in response to feelings of social isolation and lack of social support from people．

    Heat has been used to control hair for hundreds of years. But how much is too much? If you have ever opened a very hot oven, you know that heat can burn your eyebrows off your face very quickly. A scientist from Purdue University in Indiana is trying to find a scientific answer on how hot is too hot when it comes to your hair.

    Many women and some men are very particular about their hair. Some people who have naturally curly hair prefer to have it straightened. Others with straight hair want to have curls. Tahira Reid is one of those people. As an African-American woman, she is familiar with the challenges of maintaining (保养)curly hair.

    Tahira Reid and other researchers at Purdue University are studying how heat treatment interacts with different types of hair and how to prevent damage. Amy Marconnet is an assistant professor. She says the team is seeing how heat and temperature relate to their research.

    In a Purdue University's lab, team members designed a hair straightener tool —a flat iron with temperature control. They attached it to a robotic arm that moved over pieces of hair. They controlled the temperature while the device straightened hair.

    What did they find? Their study found that the heat weakens or breaks a protein called keratin, responsible for the hair's shape, and temporarily changes it. But nobody knows exactly what level can make the heat actually cause forever change. Researchers say early results are a bit inconclusive.

    It turns out that everyone's hair is different and there's no exact temperature where hair straightening becomes hair damage. Ms Reid says they will continue their research in the hope of finding what works best without damaging hair.

    Photos of eight-year-old Wang Fuman, nicknamed by “Snowflake Boy” in Yun Nan, shared by his principal on Tuesday, showed the boy has a red face from the low temperatures and apparently did not wear enough clothes to keep warm. He also suffered from frostbite. He stood alone with his white hair and eyebrows while other classmates behind were clearly amused and laughing. The picture drew widespread attention around the whole world. Many netizens (网民) were sympathetic to the boy's difficulties, with many Mircoblog users giving comments under the report.

    Just after the report, a donation of 100,000 yuan was sent to his Primary School. Constantly, help still pours in for the Chinese boy. But the local authorities call on others to pay attention to other similar rural areas and give them timely aid. In China, there are still so many children just like Fuman living by himself with parents migrating to cities to make a living.

    Babies' main food is rice cereal. But it is often poisoned. Studies have found that many brands contain measurable amounts of inorganic arsenic(无机砷),the most poisonous kind. It's not just nice: an August 2018 study tested 50 foods made for babies, including organic and nonorganic brands such as Gerber, Earths Best, and other popular labels, and found evidence of at least one dangerous heavy metal in every product. Fifteen of the 50 contained enough contaminants(污染物)to pose potential health risks to a child eating one serving or less a day.

    Heavy metals can damage cognitive(认知的)development in children, who are especially at risk because of their smaller size. Inorganic arsenic in drinking water has been found to lower the IQ scores of children by five to six ills. And as heavy metals accumulate in the body over time, they can raise the risk of cancer, diabetes and other physical conditions. Of course, finding you're your favorite brand is contaminated is not a reason to panic. Low levels of exposure for short periods are unlikely to cause serious effects, but parents should focus on reducing the overall levels of these poisonous substances in their children's total diet to limit harm.

    Heavy metals occur naturally on Earth and are present in soil and water. But pesticides(杀虫剂), mining and pollution increase their concentrations, and farming and food manufacturing processes can contribute even more.

    Food makers are clearly of keeping baby food poison-free: roughly a third of the tested products did not contain worrisome metal levels. Some companies are already trying to look into the sources of contamination in their products and try to reduce them. More companies should follow. But the best chance of real change will come with laws. Currently there are no U. S rules on acceptable levels of heavy metals in baby foods.

    The government and the food industry should unite to deal with the serious threat to our children.

    The United States estimates that about one out of every 10 people on the planet today is at least 60 years old. By 2050, it's projected to be one out of 5. This means that not only will there be more old people, but there will be relatively fewer young people to support them.

    Professor Richard Lee of the University of California at Berkeley says this aging of the world has a great effect on economics. "Population aging increases the concentration of population in the older ages and therefore it is expensive," he said.

    Aging populations consume (消耗) more and produce less. With more people living longer, it could gel expensive. But Mr. Lee says with continuing increases in worker productivity and wise planning, it can be manageable.

    Societies have different methods for caring for the elderly，but each carries a cost Generally, there are three types of support Seniors can live off the wealth they gained when they were younger. They can rely on their family to take care of them, or they can rely on the movement.

    In industrialized nations, governments created publicly-funded (公共资助的) support systems. These worked relatively well until recent years, when aging population growth in places like the United States and Western Europe began to gradually weaken the systems' finances(资金). These nations now face some tough choices. Mr. Lee says the elderly in some of these countries must either receive less money, retire later or increase taxes to make the system continuable.

    Most developing nations haven't built this type of government-funded support, but have instead relied on families to care for their elderly. These nations also generally have a much younger population, which means their situation is not as urgent as more developed nations. But Mr. Lee says that doesn't mean they can pay no attention to the issue. "Third World countries should give very careful thought to this process, to population aging and how it may affect their economies — now, before population aging even becomes a problem," he explained.

"WOW, THIS is not what I was expecting at all," says Allison, a nurse, remembering the first romance novel she ever read. Having shared the general literary bias (偏见) towards romance novels, she is now crazy about this genre (体裁). Allison was browsing in The Ripped Bodice, a romance-novel shop that recently opened in Brooklyn. The day the shop opened, the queue to get in was more than an hour long. The shop, which is uniquely-decorated, is serious in its devotion to romance novels.

The popularity of The Ripped Bodice (the second chain store devoted to romance in the district) is part of a larger shift. During the pandemic, when many were stuck at home and looking for escapist reading, fictional romance blossomed. In the year to May, romance print sales were up by 52%, according to a market-research firm. List-price sales grew by 74%. Annual growth in sales went from 6% in 2020 to more than 50% last year.

Readers have changed too. Newer fans are mostly young adults and many are teenagers. They are keen on romance novels with a central love story and a happy ending. 

"The industry has a lot of respect for what has been happening with romance," says Kristen, the manager of the market-research firm. "Now modern authors want to seek something deeper. Love is a powerful feeling. I wish that the writers could all see their way past thinking that those emotions are somehow less valuable than emotions that are built out of pain and sorrow," says Sarah, author of "Knockout"－a best-seller about romance in this season.

Librarians have noticed the shift too. Stephanie Anderson, of BookOps, which buys books for public libraries in New York and Brooklyn, notes that "the biggest challenge with romance at this point is finding the money and space to keep up with all the popular titles."