Most animals have little connection with animals of a different kind, unless they hunt them for food. Sometimes, however, two kinds of animals come together in a partnership (伙伴关系) which is good for both of them. You may have noticed some birds sitting on the backs of sheep. This is not because they want a ride, but because they find easy food in the parasites (寄生虫) on sheep. The sheep allow the birds to do so because they remove the cause of discomfort. So although they can manage without each other, they do better together.

    Sometimes an animal has a plant partner. The relationship develops until the two partners cannot manage without each other. This is so in the corals(珊瑚) of the sea. In their skins they have tiny plants which act as “dustmen”, taking some of the waste products from the coral and giving in return oxygen which the animal needs to breathe. If the plants are killed, or are even prevented from receiving light so that they cannot live normally, the corals will die.

    Charlotte Heffelmire was home in Vienna,Va.,for Thanksgiving break from the Air Force Academy when she saw that her father had gotten stuck under the pickup truck he'd been working on.

    "I was on my back,face up,and I was trying to get some brake lines when apparently the jack（千斤顶）slipped and fell down on me,"her dad,Eric Heffelmire,told WUSA9.Gasoline spilled（溢出）and caught fire,and he knew he was in trouble."I thought they 'd be pulling out a dead body later in the evening."

    After his struggling for 10 minutes,his barefoot teenage daughter came running into the garage."I felt the weight shift,and I said,'You almost got it.'and then it was just UGHHHRRR,and suddenly I'm pulled out,"Eric told NBC4.

    Even Charlotte,120 pounds and 5-foot-6,isn't sure where her power came from."It was some crazy strength, "she told WUSA9.

    Realizing the burning truck could set her house on fire at any moment,Charlotte jumped into the truck and drove it out of the garage."I didn't want the entire house to explode with the truck,so I started the truck,put it in four-wheel drive,and managed to drive it with three wheels,"she said.

    Then she went inside the house to grab her baby sister and got her grandmother out of the house too."I just did what I had to do,so I don't feel like a big hero or anything,"Charlotte said.Her local fire department,Fairfax County Fire and Rescue,felt differently,awarding her the Citizen Lifesaving Award.

A Teenage Inventor

    The world could be one step closer to quick and inexpensive Ebola detection thanks to a teenager from Connecticut.

    Olivia Hallisey, a junior at Greenwich High School, was awarded $50,000 in the Google Science Fair for her new method that detects Ebola, a virus that causes bleeding from different parts of the body and usually causes death. Olivia's method is to ask patients to put their saliva (唾液) onto a testing card. The card changes color if the person is catching Ebloa. Present Ebloa tests take up to 12 hours and cost $1,000. Olivia's method, however, can be done just in 30 minutes for about $25. Besides, the sample (样本) doesn't have to be put in a refrigerator thanks to the silk material Olivia uses to produce the testing cards.

    Olivia was inspired to deal with this global problem after watching the news that more than 10,000 people died from Ebola in West Africa. She was particularly worried about the fact that, while the acts of involvement can improve survival rates, present detection methods are costly, time-consuming and require complex tools. Olivia got help from her science research teacher. She drew out directions from past research, and figured out detection systems that have proven to work with other diseases, including Lyme disease and yellow fever.

    "What affects one country affects everyone," Olivia told CNBC. "We have to work together to find answers to the huge challenges which cause harm to the global health." The Connecticut's teen, who hopes to become a doctor one day, was named the Google Science Fair winner in the competition of 20 competitors from across the globe. The fair is open to young people between the ages of 13 and 18 in most countries.

    Olivia hopes her success will inspire other girls interested in science and computers. "I would just encourage girls to try it in the beginning, and remind them that they don't have to feel naturally drawn or feel like they have a special talent for maths or science," she told CNBC, "but just really look at something they are interested in and then think how to improve something or make it more enjoyable or relate it to their interests."

    Even though it's the 18th movie from the Marvel Universe, Black Panther is the first one to feature a black superhero with a primarily black cast(演员阵容).

    The film tells the story of the Black Panther, a superhero who takes his father's place as king of the fictional African country Wakanda. The film came out in Chinese mainland cinemas on March 9, passing the $1 billion (about 6 billion yuan) mark at the global box office and becoming the No. 2 superhero release of all time on March 10.

    However, Black Panther means more than just the money it's making. As the Guardian noted, the film is already being regarded as "a positive force for social change".

    The wild success of Black Panther lies in the fact that it gives voices to minorities who are rarely given room in popular culture. "It carries a weight that neither Thor nor Captain America could lift: serving a black audience that has long gone under-represented," Time noted.

    "It makes me feel proud and confident that we made it on screen in that way," Rasheed Butler, 14, from a black community in California, US, told the Marin Independent Journal.

    The superhero Black Panther is inspiring, but the movie also highlights brilliant black women. For example, Black Panther's teenage sister is a tech genius. She designs gadgets for her brother and develops resources that make the isolated Wakanda wealthy scientifically and technologically advanced.

    "What I love about the way this film represents women is that each and every one of us is an individual, unique," Kenyan-Mexican actress Lupita Nyong'o, who plays a spy in the movie, told the Los Angeles Times. "I think that's a very powerful message to send to children – both male and female."

    Powerful characters aside, the movie has social implications. While the Black Panther tries to keep his country and people away from the outside world, others want to make use of Wakanda's advanced technology to fight injustice. "But neither option is truly tenable," The Verge noted. "It suggests that these destructive cycles may only be broken through guidance, education, and global leadership."

    Instead of hiding away from current issues of race and economic differences, the movie explores what it means to be black in the US, in Africa and in the world. It deals "head-on with the issues affecting modern-day black life", Time concluded.

    A walk through the galleries of Quebec's Montreal Museum of Fine Arts (MMFA) places individuals face-to-face with some 43,000 artworks ranging from Chinese ceramics(陶瓷制品) to Inuit sculpture.

    While the visiting is an incredible cultural experience, a group of local physicians will soon be able to prescribe(开处方) museum visits as treatment for some illnesses.

"We know that art contributes to neural(神经的) activity," said MMFA director Nathalie Bondil. "What we see is that being in contact with art can really help your well-being."

Hélène Boyer, vice president of a Montreal-based medical association, explains that museum visits have been shown to increase levels of serotonin, a neurotransmitter(神经传导物质) known as the "happy chemical" which helps to lift mood.

    According to Boyer, the small increase in hormones(荷尔蒙)associated with enjoying an afternoon of art is similar to that offered by exercise, making museum prescriptions ideal for the elderly experiencing pain that prevents them from regularly joining in physical activity.

    The museum visits are designed to improve traditional methods. As Bondil notes, spending time in a peaceful environment can provide a welcome distraction. "What is most important is this experience can help them escape from their own pain," she says. "When you enter the museum, you escape from the speed of our daily life."

    "I am convinced that in the 21st century, culture will be what physical activity was for health in the 20th century," said Bondil. "Some people would do well to recall that just in the 19^th century, sports were believed to do harm to the body. Just as doctors now prescribe exercise, they will be able to prescribe a visit to the MMFA."

    Bill Gates and the president of General Motors have met for lunch, and Gates is going on and on about computer technology. "If automotive technology had kept pace with computer technology over the past few decades, you would now be driving a V-32 instead of a V-8, and it would have a top speed of 10, 000 miles per hour," says Gates. "Or, you could have an economy car that weighs 30 pounds and gets a thousand miles to a gallon of gas. In either case, the sticker price of a new car would be less than $50.Why haven't you guys kept up?"

    The president of GM smiles and says, "Because the federal government won't let us build cars that crash four times a day."

    Why is that funny (or not funny, as the case may be)? Human beings love to laugh, and the average adult laughs 17 times a day. Humans love to laugh so much that there are actually industries built around laughter. Jokes, sitcoms and comedians are all designed to get us laughing, because laughing feels good. For us it seems so natural, but the funny thing is that humans are one of the only species that laughs. Laughter is actually a complex response that involves many of the same skills used in solving problems.

    Laughter is a great thing—that's why we've all heard the saying, "Laughter is the best medicine." There is strong evidence that laughter can actually improve health and help fight disease. In this article, we'll look at laughter—what it is, what happens in our brains when we laugh, what makes us laugh and how it can make us healthier and happier. You'll also learn that there's a tremendous amount that no one understands yet.