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Longer Lives for Wild Elephants

Most people think of zoos as safe places for animals, where struggles such as difficulty finding food and avoiding predators don’t exist. Without such problems, animals in zoos should live to a ripe old age.
But matter may not be true for the largest land animals on Earth. Scientists have known that elephants in zoos often suffer from poor health. They develop diseases, joint problems and behavior changes. Sometimes, they even become infertile or unable to have babies.
To learn more about how captivity affects elephants, a team of international scientists compared the life spans of female elephants born in zoos with female elephants living outdoors in their native lands. Zoos keep detailed records of all the animals in their care, documenting factors such as birth dates, illnesses, weight and death. These records made it possible for the researchers to analyze 40 years of data on 800 African and A
A. They do not like living in herds.
B. They do not get enough exercise.
C. They do not live with their families.
D. Both Ｂ and Ｃ.

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