Today, the world's diversity (多样性) of food crops is quickly decreasing. But scientists around the world are taking action. They are building seed banks. At seed banks, scientists store the seeds of many different crops.

    There are now 1,400 seed banks around the world. However, some banks are in warm countries. If the electricity fails, the seeds will get too hot and die. Other seed banks are in countries troubled by war. Sometimes people damage the seed banks. If this happens, valuable seeds can be lost forever!

    The organization Global Crop Diversity Trust decided they wanted to deal with this problem. So, they decided to build a global seed bank. This seed bank would contain a back-up, or extra copy, of all the world's seeds. Smaller seed banks would still collect and keep local seeds. But they would also send copies of their seeds to the global bank.

    Scientists from the Global Crop Diversity Trust chose the cold, snowy mountains of Svalbard, Norway to build the global seed bank — the Svalbard Global Seed Vault (斯瓦尔巴全球种子库). Organizations, farmers, or local seed banks store their extra seeds there. And the people who place their seeds in the vault are the only people who can take them out. They pay to ship their seeds to Norway, but it does not cost them any money to store their seeds. The Global Crop Diversity Trust pays for this.

    Cary Fowler is a scientist who heads the Global Crop Diversity Trust. He said, “If the Seed Vault simply supplies seed banks with copies of seeds that those banks lost by accident, the Seed Vault will be worth more than it cost.”

    The four theme parks below offer the most thrilling(刺激的)rides and attractions in the world.

Busch Gardens Williamsburg

    Located(坐落)in Virginia, USA, this theme paprk has some of the highest-rated thrill rides in the world. The park's famous roller coasters include Apollo's Chariot, Alpengeist, Griffon, the Loch Ness Monster and Verbolten. The park also has thrilling water rides, rides for kids, other rides, shows, tours, animal exhibits and more. Divided into nine areas representing European countries, the park has won an award for the quality of its food.

Everland

    One of the world's most popular theme parks, Everland is located in Yongin, Gyeonggi-do province, South Korea. The park has 40 thrill rides, including a world-famous wooden roller coaster, and many other attractions such as an hunting ride, a zoo, indoor and outdoor water parks, shows and more.

Blackpool Pleasure Beach

    This Lancashire amusement park is one of the most visited theme parks in the United Kingdom. Among the park's 125 rides and attractions are the tallest and faster roller coaster in the U. K., a classic wooden roller coaster, a steel tower ride, the biggest indoor dark ride in the world, a host of rides for kids and more.

PortAventura World

    Located on Spain's Costa Daurada, this park is divided into six themed areas. Five areas represent different locations including Polynesia, Mexico, the American West, China and the Mediterrancan. The sixth and newest area has a Sesame Street theme. The park has many rides and attractions suitable for visitors of all ages.

    Gift buying for 11 to 14-year-olds can produce memories of that classic complainer. “This gift is too old.” “This gift is too young.” “This gift was popular, like, five minutes ago.” Don't stress. Our fun gifts are sure to make you smile.

—Judy Sutton Taylor

    Snowball Launcher

The kids on your list will be happy to drop their electronic devices and head outside during the next big snowstorm thanks to this gift that launches snowballs up to 70 feet. A practice target is included to ensure they're ready for a hard battle. $16.97 at amazon.com

    Nintendo Switch

    Gamers went crazy for this mixed gaming system when it was released last spring, and it was in consistently short supply until now. The device allows users to play solo or with a friend, connect it to a TV to play on a big screen, unfold the stand for tabletop competitions, or use it for hand-held play. $299.99; links to licensed retailers at nintendo.com or amazon.com

Mertritte Animal Headphone

    Tunes will no doubt sound sweeter to lovers of any music genre when they5re coming from these cute-as-can-be headphones designed by celebrity stylists Emily Current and Merritt Elliott. The gold finish adds some fun flare (闪光装置) that is sure to inspire copycats. $59 at pbteen.com

BBOP Balls

    If there's a more entertaining way to settle sibling differences than having warring brothers and sisters bump into each other putting on mega-sized bubble armor (盔甲), we'd like to know about it. Chances are, even what may seem like the most catastrophic conflicts will end in belly laughs after a few rounds wearing these. $69.98 for a set of two at hearthsong.com or amazon.com.

Senses That Work Together

    When we think about how our senses work, we usually imagine them operating separately: you sniff a flower, and the smell is delivered uninterrupted from nose to brain. However, it's more complex than that. Most evidence for cross-modal perception (知觉) comes from studies into sound and vision (视觉). But research that shows other senses crossing over is coming out all the time, and it seems that even sound and smell sometimes form an unlikely pairing.

    When New York researchers, Daniel Wesson and Donald Wilson, tried to find out the truth about a “mysterious” area of the brain called the olfactory tubercle (嗅结节)，they had to deal with this fact. Originally, they only intended to measure how olfactory tubercle cells in mice responded to smell. But during testing, Wesson noticed that every time he put his coffee cup down with a clunk (哐啷声)，the mouse cells jumped in activity. In fact, the olfactory tubercle is well-placed to receive both smell and sound information from the outside world. Later they found that among separate cells, most responded to a smell but a significant number were also active when a sound was made. Some cells even behaved differently when smell and sound were presented together, by increasing or decreasing their activity.

    Of course, mice aren't people, so research team has been carrying out further experiments. They pulled together a group of people and gave them various drinks to smell. Participants were asked to sniff the drinks, and then match them to appropriate musical instruments and produce the notes at different levels. The results were interesting: piano was regularly paired with fruity fragrances; strong smells sounded like the instruments that are made of metal.

    Further research found that listening to different sounds can change your perceptions. Studying taste this time, the team ordered some special toffee (太妃糖)and put together “soundscapes” corresponding to bitterness and sweetness. Participants tasted similar pieces of toffee while listening to each soundscape, and found the toffee more bitter or sweeter, depending on which soundtrack they were listening to.

    Studies like this are helping scientists correctly describe our understanding of the senses, and how the brain combines them with its advantage. The consequences are worth considering. Could we see musicians work together with chefs to produce sound-improved food and drink? Will you be ordering a coffee with a soundtrack to bring out your favorite smell? Come to think of it, that could be one thing you hope coffee shop chains don't get round to.

    (CNN)—This photograph of two men sharing a drink 30 meters below the water is part of an art project exploring the mysterious world of freediving—a form of underwater diving that relies on a diver's ability to hold his or her breath until resurfacing rather than on the use of oxygen tanks (氧气瓶).

    Each man, dressed in shirt, jeans and sunglasses, sits in a chair at the bottom of the Caribbean Sea with local sharks—harmless to humans—swimming just meters away. Of course, these aren't ordinary men, but freedivers: extreme athletes who dive on a single breath of air.

    American photographer Lia Barrett had been taking pictures of brave divers competing at the Caribbean Cup off the coast of Honduras, when she decided to create a fantastic underwater world in which humans go about everyday tasks—such as drinking coffee or riding bikes.

    "After the competitors had a great time in the new national and world records set at the competition, I took advantage of their breath-holding skills to do photo shoots I had only dreamed of before," said the 29-year-old.

    Perhaps unsurprisingly, Barrett is often asked whether the amazing pictures are Photoshopped. She laughs quietly as she insists they're 100% real.

    The picture of two men having coffee took 50 minutes to create, with the men receiving oxygen from standby assistants around every three minutes.

    "On the way back up, we were holding onto the table during our decompression (减压) stop in the strong current (水流)—it was quite a scene."

    The underwater models made an 11-minute stop on the way back to the surface, making sure they didn't rise too quickly and suffer decompression sickness—which can cause deadly blackouts (眩晕).

    The term "crocodile tears" refers to insincere sadness. This term has an etymology dating back several centuries. As early as the fourth century, crocodile tears are referenced in the literature with the meaning of insincere sorrow. It is said that crocodiles weep while eating their hunted animals because they are sad; however, this sadness is not honest.

    The term crocodile tears became widely popular after it was documented in a fifteenth-century book titled The Voyage and Travel of Sir John Mandeville, Knight. A passage from the book reads: "These crocodiles kill men and they eat them weeping."

    As you may already know, crocodilians(鳄目动物) likely feel bad about little—especially feeding. However, the assumption of the crocodile-tears metaphor may be true. In a 2007 paper published in BioScience titled "Crocodile Tears: And they eat them weeping", researchers observed 7 crocodilians in cages during feeding time at a reserve (4 caimans and 3 American alligators). The researchers observed the crocodilians outside of water at feeding stations to better find out whether tearing developed.

    Five of the 7 crocodilians developed something like tears in their eyes before, during or after feeding. The researchers suggest that these crocodile tears occur because a crocodilian hisses (发出嘶嘶声) while it eats, and this hissing forces air through the spaces in the bone behind the nose and out the eye, in the process picking up nasolacrimal secretions (鼻泪管分泌物.)

    In humans, crocodile tears is a medical condition that causes a person to tear up while eating. Crocodile tears typically occur because of a temporary loss of facial control due to damage of the facial nerve. Specifically, when the facial nerve grows again, it does so incorrectly thus resulting in tears during chewing food.