RC 2

The golden toad of Costa Rica, whose beauty and rarity inspired an unusual degree of human interest from a public generally unconcerned about amphibians, may have been driven to extinction by human activity nevertheless. In the United States, a public relations campaign featuring the toad raised money to purchase and protect the toad's
habitat in Costa Rica, establishing the Monteverde Cloud Forest Preserve in 1972. Although this action seemed to secure the toad's future, it is now apparent that setting aside habitat was not enough to save this beautiful creature. The toad's demise in the late 1980s was a harbinger of further species extinction in Costa Rica. Since that time, another twenty of the fifty species of frogs and toads known to once inhabit a 30 square kilometer area near Monteverde have disappeared.

The unexplained, relatively sudden disappearance of amphibians in Costa Rica is not a unique story. Populations of frogs, toads, and salamanders have declined or isappeared the world over. Scientists hypothesize that the more subtle effects of human activities on the world's ecosystems, such as the build-up of pollutants, the decrease in atmospheric ozone, and changing weather patterns due to global warming, are beginning to take their toll. Perhaps amphibians - whose permeable skin makes them sensitive to environmental changes - are the "canary in the coal mine," giving us early notification of the deterioration of our environment. If amphibians are the biological harbingers of environmental problems, humans would be wise to heed their warning.

1. According to the passage, all of the following are true EXCEPT:
· Humans are at least partially responsible for changing weather patterns.
· Toads, like frogs, have permeable skin.
· Human activity is not necessarily responsible for the global decline of amphibious populations.
· Costa Rica's Monteverde Cloud Forest Preserve was not paid for solely by the Costa Rican government.
· More frog and toad species than salamander species have disappeared in Costa Rica since the late 1980s.

2. It can be inferred from the passage that
· only thirty species of frogs and toads remain in Costa Rica
· humans do not have permeable skin
· the build-up of pollutants in the atmosphere causes a decrease in atmospheric ozone
· humans do not usually take signals of environmental deterioration seriously
· Costa Rica suffers from more serious environmental problems than many other countries

3. The author uses the adjective "subtle" in the second paragraph most probably to emphasize that
· these effects are not easily recognized by sophisticated testing equipment
· these effects are difficult to notice because they take place over time on a global scale
· these effects are so minimal that they affect only small animal species such as amphibians
· these slight effects of human activity are rarely discussed by scientists
· these effects are infrequently observed because they affect only specific world regions

4. The passage implies that
· many amphibians are not considered beautiful.
· the Monteverde Cloud Forest Preserve was not large enough to protect the golden toad.
· only Costa Rican amphibians living near Monteverde have disappeared since the 1980s.
· amphibians sometimes live in coal mines.
· no humans yet consider the decline of amphibious populations an indication of a threat to human populations.

5. The primary purpose of the passage is to
· discuss the mysterious disappearance of Costa Rica's golden toad.
· explain why human activity is undoubtedly to blame for the global decline of amphibious populations
· convince humans that they must minimize the global output of pollutants.
· describe the recent global decline of amphibious populations and hypothesize about its causes.
· urge humans to pay careful attention to important environmental changes.

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