单选题. Traffic fumes render the scent of flowers barely recognizable to honeybees and could have a serious impact on their ability to find food, new research has found. Scientists discovered that reactive pollutants in diesel (柴油) destroyed key chemicals in the odour of oilseed flowers making them smell different to the bees. "Honeybees have a sensitive sense of smell and an exceptional ability to learn and memorize new odours," said Tracey Newman, a neuroscientist at the University of Southampton. "The effects of diesel fumes on flower scent could have serious detrimental effects on the number of honeybee colonies and pollination (授粉) activity." Three-quarters of the world's food crops rely on bees and other natural pollinators. "Pollinator services are crucial to humankind," said Newman. But, there have been serious declines in natural pollinators in recent decades. A combination of factors is blamed, including the huge loss of the flower-rich habitats that sustain bees, as well as disease, and the impact of agricultural insecticides. The revelation that traffic fumes could be adding to the problems is significant, said Guy Poppy, a professor and ecologist at Southampton, who also worked on the research. He said, "Diesel exhaust is not the root of the problem, but clearly, with all the other stressors, adding another one is likely to be detrimental to bee health." The study, published in the journal Scientific Reports, tested bees' ability in the laboratory to recognize the aroma of oilseed rape flowers. Bees were strapped down and taught to associate floral scents with food in the form of sugar solutions. Once the bees learned the connection they began sticking their tongues out in anticipation of food even if it was not offered—an indication that they recognized the smell. When the scent was presented without pollutants the bees recognized it 98%～99% of the time. But after the scent was mixed with levels of diesel exhaust matching those found at roadsides, the bees only recognized it 30% of the time.21. What is the influence of reactive pollutants in diesel? ______
【正确答案】
B
【答案解析】 一项新的研究发现，汽车尾气改变了花的气味，使蜜蜂几乎无法辨认，这对它们寻找食物的能力带来了严重影响。科学家们发现，柴油的活性污染物破坏了油菜花气味中关键的化学物质，让蜜蜂闻到的是不同的气味。发表于《科学报告》杂志上的研究测试了蜜蜂在实验室辨认油菜花香味的能力。当提供的气味中没有混入污染物时，蜜蜂98%～99%的时间都能分辨出那种气味。但像在路边发现的花那样，在香味中混入不同程度的柴油车尾气时，蜜蜂辨认出那种气味的几率只有30%。 细节理解题。由文章第一段第二句Scientists discovered that reactive pollutants in diesel destroyed key chemicals in the odour of oilseed flowers making them smell different to the bees可知，“柴油的活性污染物破坏了油菜花气味中关键的化学物质，让蜜蜂闻到的是不同的气味”。与B项“改变了油菜花的香味”一致，答案为B。A“破坏了油菜花”，这一信息不够确切。C“污染了空气”，文章并未指出这一点。D“损害了蜜蜂的嗅觉”是断章取义，也不对。