Where Have All the Bees Gone? Scientists who study insects have a real mystery on their hands. All across the country, honey

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问题                       Where Have All the Bees Gone?
    Scientists who study insects have a real mystery on their hands. All across the country, honey bees are leaving their hives(蜂巢) and never returning. Researchers call this phenomenon colony-collapse(群体瘫痪) disorder. It is reposed that 25 to 40 percent of the honeybees in the US have vanished from their hives since last fall. So far, no one can explain why.
    Colony collapse is a serious concern because bees play an important role in the production of about one-third of the foods we eat. As they feed, honeybees spread pollen(花粉)from flower to flower. Without this process, a plant can’t produce seeds or fruits.
    Now, a group of scientists and beekeepers have teamed up to try to figure out what’s causing the alarming collapse of so many colonies. They hope to find out what’s contributing to the decline and to prevent bee disappearance in the future.
    It could be that disease is causing the disappearance of the bees. To explore that possibility, Jay Evans, a researcher at the United States Department of Agriculture (SDA)  Bee Research Laboratory, examines bees taken from colonies that are collapsing. "We know what a healthy bee should look like on the inside and we can look for physical signs of disease. " he says. And bees from collapsing colonies don’t look very healthy. "Their stomachs are worn down compared to the stomachs of healthy bees. " Evans says. It may be that a parasite(寄生虫) making the bees’ digestive organs. Their immune(免疫的)systems may not be working as they should. Moreover, they have high levels of bacteria inside their bodies.
    Another cause of colony-collapse disorder may be certain chemicals that farmers apply to kill unwanted insects on crops, says Jerry Hayes, chief bee inspector for the Florida Department of Agriculture. Some studies, he says, suggest that a certain type of insecticide (杀虫剂)affects the honeybee’s newels system and memory. "It seems like honeybees are going out and getting confused about where to go and what to do. " he says.
    If it turns out that a disease is contributing to colony collapse, bees’ genes could explain why some colonies have collapsed and others have not. In any group of bees there are many different kinds of genes. The more different genes a group have, the higher the group’s genetic diversity. So far scientists haven’t determined the role of genetic diversity in colony collapse, but it’s a promising theory, says Evans.
What is the mystery that researchers find hard to explain?

选项 A、Honeybees are flying all across the country.
B、Half of the honeybees in the US have died
C、Honeybees are leaving their hives and do not return.
D、Honeybee hives are in disorder.

答案C

解析 本题是细节题。原文是:“研究昆虫的科学家目前有一未解谜团。全国的蜜蜂正在离开自己的蜂巢并不再返回了。”问题是:“科学家发现不好解释的这个谜团是什么?”因为选项C“蜜蜂离开家园并不再回来”正是文中所述答案,其他选项意思不符,因此选C。
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