Bees and other pollinators（传粉者）  use smells to track down fresh flowers. Air pollutants can weaken those scents（气味）.  Scientists had worried this might make it harder for some pollinators to find a meal.

    Many animals help pollinate plants. Species that do this include bees, butterflies, etc. But for many reasons, the pollinators available to help plants in this way are decreasing. Scientists think a loss of habitat（栖息地）can be one factor. Diseases and exposure to poisonous chemicals also count.

    Jose Fuentes points to air pollution as another possible factor. He's an atmospheric scientist at Pennsylvania State University. In an earlier study, he showed some air pollutants could weaken or destroy scents emitted(发出)by flowers.

    Searching for a meal leaves pollinators out in the open and at risk of becoming other animal's lunch. And any time spent hunting food is time away from their duties back home, like protecting a hive（蜂巢）or nest, explains T'ai Roulston. He's an insect biologist at Virginia University. Roulston worked with Fuentes on the new study.

    In the study, the researchers focused on five kinds of representative scent molecules(分子)plants emit. One molecule they looked at, for example, is called beta-myrcene. Many flowers give off this chemical into the air.  Normally, this gas can travel some 800 meters from its flower source. But in polluted air, this same molecule could travel only half as far.

    Worse still, air pollution might do more than just weaken scent plumes（气味烟云）．Chemical reactions between air pollutants and plumes may transform the flowers' smells, creating new scents. And these scents may be unrecognizable to pollinators.

    That's certainly Fuentes' concern.  So, he says his next research project will look at how insects handle any new flower scent. "It's possible that some insects will change ways to detect and use these new molecules to find food," he says.

    In 1986, the Honda automotive company wanted to see if it could make a human-like robot, to help in home, play football, balance on one foot, and even dance. Over the years there were some problems but soon the researchers managed to get a robot named ASIMO. It could walk on uneven(不平坦的) surfaces, and move its center of gravity like we do to climb stairs.

    More recently, ASIMO was improved so it could turn round and run at six kilometers per hour, using its upper body to control movement.

    ASIMO is designed to be friendly. It is hoped that robots like this could be used to help elderly people in their home. Honda are also using this technology to help people with disabilities. It can also push a cart(手推车) and open and close doors. ASIMO can even shake hands. It stands 120 centimeters tall, so that it can look into adult faces when they are sitting down. It can hold two kilos in its hands. It can even carry a tray without dropping the contents.

    So, where next for this kind of robot? Well, while ASIMO is attractive, it is still controlled by a human. Researchers in the USA are working on the robots that can learn about the world around them, and give a reply to human touch and voice. The robots are even learning to recognize(辨认) objects, people and vocabulary. Soon the descendants(后代) of these robots may be serving you drinks or helping with jobs at home and at work.

 《舌尖上的中国》聚焦普通人家的家常菜，让海内外观众领略了中华饮食之美，如图所示是一盘我们冬天特别爱吃的莴笋炒腊肉，对烹制过程中所含的物理知识，认识正确的是（　　）