In colonies (群体) that range in size from a few hundred to tens of millions, they organize their lives with a clear division of labor. Even more amazing is how they achievethis level of organization. Where we use sound and sight to communicate, ants dependprimarily on pheromone (外激素), chemicals sent out by individuals and smelled or tastedby fellow members of their colony. When an ant finds food, it produces a pheromone that will lead others straight to where the food is. When an individual ant comes under attack or is dying, it sends out an alarm pheromone to warn the colony to prepare for a conflict as a defense unit.

         In fact, when it comes to the art of war, ants have no equal. They are completely fearless and will readily take on a creature much larger than themselves, attacking in large groups and overcoming their target. Such is their devotion to the common good of the colony that not only soldier ants but also worker ants will sacrifice their lives to help defeat an enemy.

         Behaving in this selfless and devoted manner, these little creatures have survived on Earth, for more than 140 million years, far longer than dinosaurs. Because they think as one, they have a collective (集体的) intelligence greater than you would expect from itsindividual parts.

    April is Financial Literacy Month，when Americans of all ages are encouraged to learn how to be smart about money.And this year，fifth­grade Rachel Kelly from Naperville，Illinois，is already at the head of her class.Kelly,11, won a nationwide contest called the Stock Market Game.

    Students who take part in the Stock Market Game，run by the SIFMA Foundation，a financial­education organization，pretend to buy stocks (股票) worth $100,000.Then they have to read financial news over several days to see if their investments would have gained money or lost money and write an article explaining their choices.

    “I  wanted  to  choose  a  company  that was well­known，” writes Kelly.“I thought about products that I see every day，so cars came to my mind.” Kelly picked the Japanese car company Honda Motors.“Honda Motor Company is the No.1 producer of motorcycles in the world and the fifth­largest producer of automobiles behind Toyota，Volkswagen，General Motors and Hyundai，” says Kelly.

    Honda makes many different kinds of cars，which Kelly thinks makes the company a safe investment.She explains that even if the cost of gas goes up，Honda has a good chance of staying in business because of the company's fuel­efficient cars，which run on less gas than most cars made today.

    “If one of their departments is not doing so well，it won't affect the overall company sales，” she writes.

    Because the stock Kelly picked performed well and her article was persuasive，Kelly won this year's contest.About 600,000 students from 4th to 12th grade competed.

    Augusto Esquivel is a sculptor who, in his own words, is “crazy with comparisons of reality and potential and the balance between them.” Perhaps the best example of what he's talking about are his most famous creations: the suspended(悬挂的) button sculptures.

Made entirely from buttons hanging on various lengths of string, Esquivel's sculptures are made to look like common objects: a piano, a gumball machine, and even a toilet. If it wasn't for the clear string hanging above, these objects, these sculptures, would look solid, yet you can put your hands right through them. The process starts with him deciding on a subject and setting the acrylic （丙烯酸树脂）from where the buttons are being suspended. He buys buttons of different shapes and sizes, paints them with spray paint, and carefully hangs them. After that, it's a manner of hanging each individual button, which takes a lot of time. For his piano, for example, he individually hung over 60 pounds worth of tiny buttons.

Esquivel's sculptures, while mostly housed inside art galleries, perfectly capture one of the main principles of street art: something that is eye-catching and something that invites interaction. Often the best sculptures outside the art galleries aren't the ones behind guards and fencing, but the ones people can go right up to and touch. In Vancouver, a series of laughing old men are attracting people for pictures and to just generally hang around, but the people who simply walk by and see the sculptures almost always leave with a smile on their face. That's good street art: it draws the viewer in rather than relying on a gallery to draw in an audience and point them to certain pieces.

Esquivel's art is not only a presentation of talent, something that mentions larger philosophical questions, like the ones he stated above, but also just the right combination of interesting idea and painstaking work. One can look at his work in a critical way, or simply appreciate his idea and execution(艺术品的制作).

    Dubai(迪拜)is one of the economically richest places in the world. With its numerous malls, hotels, and beautiful beaches, Dubai has always been a popular holiday destination. This city was visited by around 5 million tourists each year. The government wanted to increase this number to 15 million. However, Dubai has only 45 miles of coastline, which is nowhere enough for so many people. To solve this problem, an island that looked like a palm tree was built in 2006, and named the Palm Jumeirah.

    The plan for the island was extraordinary. It was to host several hotels, shopping malls, restaurants, and homes. Although the initial plan was to build the island from concrete(水泥), a decision was taken to create it from sand and gravel(砾石), so as to give it a natural look.

    To make sure that this project was a success, the best engineers from across the world were employed. Engineers from Holland formed the majority in this group. To begin with, the engineers calculated the strength of storms at sea, and also the expected amount of rise in water levels due to global warming. And then they found that, the proposed location for the island was neither very wide nor deep.

    One of the difficulties the engineers came across was to put sand on the sea bed to create the breakwater(防浪堤).Finding the right sand for the project was also a daunting task, as the sand from Dubai's deserts was too fine. Instead, sand from the sea was used, as it was coarser(粗糙). Once the breakwater was built, construction of the island began.

    The Palm Island are really impressive in terms of engineering. However, these projects are so large that they may have changed the ecology of the region. Also, an immense amount of money and resources go into maintaining the islands, which is a major concern at the moment. Only time will tell if building the Palm Islands was actually a good decision.

    Why does time seem to fly by faster as we get old? You've got your aging brain to blame. This is likely due largely to the physical changes of our nerves and neurons (神经元). New research suggests 'rapid fire' abilities of the young brain allow us to process more information during youth, causing the days to seem longer earlier in life. However, as we get old, researchers say the older brain takes more time to process information.

    The new finding put forward by a Duke University researcher was published in a paper in the journal European Review this week According to Adrian Bejan, the J. A Jones Professor of Mechanical Engineering at Duke, the physical changes of our nerves and neurons play, a major role in our perception (知觉) of time as we get old. Over the years these structures become more complex and eventually begin to degrade.

    "Little babies, for example, move their eyes much more often than adults because they're processing images at a faster rate," Beian says, For older people, this means fewer images are being processed in the same amount of time, causing experiences to seem as though they're happening more quickly.

    Corals (珊瑚) are often described as undersea forests, but they are declining far more quickly than the Amazon. The coral reefs (礁) are likely to be among the first ecosystems to be wiped out by climate change.

    A temperature rise of just 1 to 2℃ can lead to the death of the algae (海藻) upon which corals depend, draining them of color and making the structure more fragile. These bleaching (脱色) events can be temporary if waters cool, but the more frequent they are and the longer they last, the greater the risk of damage is. But that's exactly what is happening. Bleaching was first observed in 1983. It was seen on a global level in 1998, then 2010, and then from 2015 to 2017. Most available scientific evidence tells us that unless we do something to limit warming to 1.5℃, we will lose 99% of the world's coral reefs in coming decades.

    But there are other threats beyond warming. Off the Philippine island of Palawan, its old reefs have been badly damaged by dirty water from the tourist holiday center, pollution from boats and overfishing. The area ought to be a shelter because it's one of the ocean regions most bearable to climate change. "Even here, we are losing our corals," said David Obura, chair of the Global Specialist Group in the International Union for the Conservation of Nature. "We need to reduce stress from overfishing, coastal development, pollution and tourism."

    "I'm a generation of scientists watching them disappear. It's very depressing," Obura said. "Above 1.5℃, in about 50 years, they will be a treasure of historic movies and pictures, but very little to see in real life. Children born today may be the last generation to see coral reefs in all their glory."