Tiny transmitters  fixed on the backs of the blue-green bees have allowed scientists to follow the insects as they fly for miles in search of rare flowers. Working in Panama, scientists caught 17 bees of the common species and fixed a 300 milligram radio light onto the back of each. The signals they sent out were used to follow their movements in and around the forest where they lived. Professor Martin, from Princeton University, US, and the Max Planck Institute for Ornithology in Germany, said, "By following the radio signals, we discovered that male bees spent most of their time in small centre areas, but could take off and visit areas farther away. One male even crossed over the shipping lanes in the Panama Canal, flying at least 5km, and returned a few days later." Researchers have struggled to follow the movements of bees before, following bees marked with paint or using radar which doesn't work well in forests. "Carrying the transmitter could reduce the distance that the bees travel, but even if the flight distances we record are the shortest distances that these bees can fly, they are impressive, long-distance movements," said Dr. Roland Kays, from New York State Museum, a co-author of the research published today in the on-line journal. "This result helps to explain how these bees' pollination  can be so rare." Pollination by bees and other insects is the key to the diversity and continued growth of flowers and trees in some forests. The new study is the first to use radio transmitters to follow bees in a forest. Similar research may now be carried in temperate forests, where bees also play a vital role. Researchers follow the movements of bees mainly to  _
learn how far they can fly at most discover how they affect the plants correct some wrong ideas about bees get to know where they enjoy living
Question: Tiny transmitters  fixed on the backs of the blue-green bees have allowed scientists to follow the insects as they fly for miles in search of rare flowers. Working in Panama, scientists caught 17 bees of the common species and fixed a 300 milligram radio light onto the back of each. The signals they sent out were used to follow their movements in and around the forest where they lived. Professor Martin, from Princeton University, US, and the Max Planck Institute for Ornithology in Germany, said, "By following the radio signals, we discovered that male bees spent most of their time in small centre areas, but could take off and visit areas farther away. One male even crossed over the shipping lanes in the Panama Canal, flying at least 5km, and returned a few days later." Researchers have struggled to follow the movements of bees before, following bees marked with paint or using radar which doesn't work well in forests. "Carrying the transmitter could reduce the distance that the bees travel, but even if the flight distances we record are the shortest distances that these bees can fly, they are impressive, long-distance movements," said Dr. Roland Kays, from New York State Museum, a co-author of the research published today in the on-line journal. "This result helps to explain how these bees' pollination  can be so rare." Pollination by bees and other insects is the key to the diversity and continued growth of flowers and trees in some forests. The new study is the first to use radio transmitters to follow bees in a forest. Similar research may now be carried in temperate forests, where bees also play a vital role. Researchers follow the movements of bees mainly to  _
A. learn how far they can fly at most
B. discover how they affect the plants
C. correct some wrong ideas about bees
D. get to know where they enjoy living
Answer: