| Most animals have little connection
with animals of a different kind, unless they hunt them for food. Sometimes,
however, two kinds of animals come together in a partnership(伙伴关系) which does
good to both of them. You may have noticed some birds sitting on the backs of
sheep. This is not because they want a ride, but because they find easy food in
parasites(寄生虫) on sheep. The sheep allow the birds to do so because they remove
the cause of discomfort. So although they can manage without each other, they do
better together. Sometimes an animal has a plant partner. The relationship develops until the two partners cannot manage without each other. This is so in the corals (珊瑚) of the sea. In their skins they have tiny plants which act as "dustman", taking some of the waste products from the coral and giving in return oxygen which the animal ne A. they can eat its parasites B. they depend on the sheep for existence C. they enjoy travelling with the sheep D. they find the position most comfortable [单项选择]How often do most places have earthquakes
A. The one in Alabama. B. The one in Alaska. C. The one in San Francisco. 我来回答: 提交
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