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.

    Patricia Blues, 29, has a new aim in life: to keep drivers' hands on their steering wheels and off their cell phones. On November 2, 2007, Blues lived through a horrible experience. A motorist dialing a cell phone drove through a stop sign at 45 miles per hour and ran into the side of Blues' car. Blues' 2-year-old daughter was killed immediately in the crash.

    Blues has since devoted her time top pushing for laws that would prevent this type of tragedy from happening again.

    Cell phones are not the only distractions（分神） that cause accidents. Eating, changing CDs, reading maps, talking to passengers, and just reaching for an object on the floor can be dangerous. Therefore, the emphasis should be on educating drivers to avoid all distractions. However, talking on cell phones might be easier to regulate than eating or changing music. At least 34 states have already passed laws to restrict cell phone use in moving cars. No state has banned it yet, but several US. cities. Worldwide, 13 nations, including Australia, England, Germany, Japan and China have banned drivers' use of cell phones in moving cars.

    To date, no scientific evidence has been published showing that talking on the phone affects driving safety. But according to a test by some high school students, “driving while on the phone does affect safety and probably shouldn't be done”.

    The brain of an insect isn't very big. But insects are somehow still able to make lots of important decisions. Bees, ants and roaches(蟑螂) build hives(巢穴)with thousands of workers doing specialized work. The jobs are done without a head or even a plan. How do insects manage this?

    To solve the mystery, scientists in Belgium spent months building robotic roaches and then putting them among real roaches. The final goal of the research is to find out how the simple behavior of individuals gives rise to a collective decision. The roach is a good starting point for trying to answer the big question because its social system is simple enough for scientists to study.

    The first step was to build robots that real roaches would accept as their own. Although the robotic roaches don't look much like the real thing, they have similarities with them in three key ways: they naturally head toward dark areas, they are influenced by the behavior of other roaches, and even more importantly, they smell like roaches.

    The next step was getting the robotic and real roaches to work together on common tasks. In experiments, the robots would collectively head towards a dark place, copying the behavior of natural roaches. That got the researchers wondering: if you program the robotic roaches to go woward the lighted place, would the real roaches follow, going against their natural instincts.(本能) ?

    They will – it turned out. Many of the real roaches followed the robots to a lighter shelter. But influence turned out to be a two- way street. On occasion, the real roaches were able to override the programming of the robot roaches and get them to turn into dark hiding places. Being social creatures, both the robotic and natural roaches were paying attention to and following the example set by others.

    In theory, it would be possible to create a robot that could influence collective decision-making in humans. To do this, researchers would have to invent a robot that people would accept. Fortunately, the technology isn't there yet.

    Farah was sitting in the kitchen going over the party list with her mother. The exams were over and Farah wanted to invite her friends for a party.

    "Farah, aren't you going to invite Hafsa?" her mother asked. Hafsa had been her best friend since childhood.

    "Mother, you know I am now a part of Purple Girls Club and we have some rules about people we can be friends with," Farah answered.

    "Really? And what are the rules?" her mother asked.

    "Well, only very pretty girls can be part of our group. And Hafsa is so...you know...dark."

    "I cannot believe it," her mother said angrily.

    As Farah left the kitchen, her father called her from the living room. Farah went to her father and paled when she saw the exam report in his hands. "Farah, what has happened to your grades? You have failed in Mathematics," her father said. Farah had no answer. The truth was that the activities of Purple Girls Club left her with very little time for studies. "Farah, it says that you can take part in supplementary exams(补考). If your grades don't improve then, I'll cancel(取消) your trip to Spain." Farah went to her room and called Gina, the leader of Purple Girls Club, "Gina, can you help me to complete my notes before the exams?" Gina laughed. "Exams? Who cares about exams?"

    One by one, she called her friends in the club but no one seemed to care or wanted to help. Farah knew Hafsa would help her. Farah also knew Hafsa had been hurt by her, but Hafsa said, "If you need any help, just let me know. We can study together till your exams." Next Monday, as two friends entered the school together, Gina called out. "Farah, you know our rules. You cannot be friends with those who do not belong to our club."

    "Gina, I have a new rule about friendship," Farah replied.

    A new study suggests climate conditions in the Sahara Desert, one of hottest, driest and most deserted areas in the world, have changed from wet to dry a about every 20,000 years.

    But previous evidence has suggested the Sahara did not always experience such extreme heat and dry conditions. At times, the Sahara Ranged to a very wet climate. This permitted plants and animals to develop and grow and led to the creation of human settlements. Now, they have discovered more evidence, which, the lead researcher David Mc Gee says, supports the idea that the Sahara's climate kept changing between wet and dry about every 20,000, years.

    McGee reported these climate changes were mainly driven by changes in the Earth's(地轴)as the planet travels round the sun .This process affects the amount of sunlight between seasons. Every 20,000 years the Earth receives more strong summer sunlight. When the Earth's axis changes again, the amount of sunlight is reduced. This season change happened continuously every 20,000 years. The other part of the season produced rainy conditions, resulting in a wetter, greener, plant-rich environment. When the rainy activity weakens, the climate becomes hot and dry, like the Sahara remains today.

    The scientists based their research on dust collected from ocean sediment(沉积物)in the Atlantic Ocean bottom off the coast of West Africa. The dust contained layers (层)of ancient sediment built up over millions of years. Each layer could contain traces of Saharan dust as well as the remains of life forms. This information was used to assess over what time period the dust had built up. This led to the overall finding that the Saharan changes from wet to dry climates happened every 20,000 years.

David McGee said that today we only see the Sahara Desert as an extremely deserted and "inhospitable" place. The new study suggests that the area's climate has changes between grasslands and a much wetter environment, and back to dry climates, even over the last quarter million years. McGee says he thinks the latest research can be valuable in studying the Sahara's history as it relates to human settlement.

    The world is a truly strange place waiting to be explored. In addition to offering a lot of extraordinary locations and people, it also offers interesting festivals celebrated by people in various parts of the world. Here is a list of the oddest festivals that can be found around the world.

    Cheese Rolling Festival: A festival that is surely going to leave you with a sore neck if not a broken one! Celebrated in England, the Cheese Rolling Festival is something that you would rather watch than take part in.

    Okay! Here's how it goes. Officials set a big cheese wheel to roll down a steep hill and participants run after it. The first one to catch it wins the competition and the cheese. Simple? Well, try it out and you will know!

    The Monkey Buffet: Now here's a country that actually feeds monkeys to their hearts' content instead of chasing them away. Celebrated in Thailand, the Monkey Buffet is an annual event that brings together a lot of locals who offer fruit and vegetables to over 600 monkeys. It's a great feast as the monkeys dig into almost 3, 000 kilograms of fruit and vegetables. The people of Thailand believe this is a way to honor the Monkey King called Hanuman.

    La Tomatina: Here's your golden chance to get even with your friends who sprayed(喷洒)paint on you on your birthday. Celebrated in Spain, the month of August has nearly 250 pounds of tomatoes go down the drain(被浪费掉)in what is perhaps the largest tomato fight in the world. The event is conducted in the town of Bunyol and attracts nearly 30, 000 tourists around the world in addition to locals. Truckloads of tomatoes arrive and you are ready to go. The entire area is covered with slush and tomatoes within minutes. It's a good time to have fun with friends and family.