Directions: There are 4 passages in this part. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A., B., C. and D. You should decide on the best choice and write down your answer on the Answer Sheet.
Passage 3
It started last year when a group of middle school children on a biology field trip in south-central Minnesota spotted some unusual-looking frogs. One was missing a leg, some had withered arms, others had shrunken eyes. Of the 22 frogs caught that day, 11 were deformed. Their teacher told officials. Reports of strange frogs began to mount: a frog with nine legs; a clubfooted frog; a frog with three eyes, one of them in its throat.
At first, investigators from the Minnesota Pollution Control Agency in St. Paul assumed that the problem was restricted to their state, and the agricultural part at that. They were wrong. Deformed frogs have since turned up in Wisconsin, South Dakota, Vermont and up into Canada.
“Abnormalities like this get me worried,” says David Hoppe, a University of Minnesota researcher. “We don’t know how far this is going to go.” Because frogs spend much of their life in water, pesticides or harmful metals were prime suspects. But now possible causes include acid rain, global warming and increased ultraviolet light. Hoppe observes that different deformities seem to be concentrated in frogs from different regions. It may be, he says, that more than one cause is at work.
What some scientists fear is that the frogs could be a sign that something is very wrong with the environment. “We may have a large problem here,” says Robert McKinnell, a University of Minnesota cancer researcher, who has collected hundreds of deformed frogs. “If frogs are not able to handle whatever it is that is causing this, it may turn out that people can’t either.”