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题库 / Prep2007E1-CR-4
A popular beach has long had a dolphin feeding program in which fish are given to dolphins several times a day; many dolphins get as much as half of their food each day there. Although dolphins that first benefit from the program as adults are healthy and long-lived, their offspring have a lower life expectancy than offspring of dolphins that feed exclusively in the wild.
Which of the following, if true, most helps to explain the lower life expectancy of offspring of dolphins feeding at the beach compared to other young dolphins?
Sharks that prey on dolphins are less common in the open seas off the beach than in many other areas of the open seas where dolphins congregate.
Many of the adult dolphins that feed at the beach are females that nurse their offspring there.
The fish given to the dolphins at the beach are the same types of fish that dolphins typically catch in the wild.
Many dolphins that feed at the beach with their offspring come to the beach only a few times a month.
Adult dolphins that feed at the beach spend much less time teaching their offspring how to catch fish in the wild than do other adult dolphins.
Although dolphins that first benefit from the program as adults are healthy and long-lived, their offspring have a lower life expectancy than offspring of dolphins that feed exclusively in the wild.
虽然成年后首次受益于该计划的海豚健康长寿，但它们的后代的预期寿命低于只在野外进食的海豚的后代。
KEY WORDS:成年后as adults才首次受益于该计划——幼时已养成野外捕食能力；只在exclusively野外进食的后代——是否也具有该能力？
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