题目内容
（请给出正确答案）
What is the killdeer's nest in parking lot an example of？
A．A primitive type of nest.
B．An elevated nest.
C．A typical cup-shaped nest.
D．A nest of twigs and branches.
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更多“What is the killdeer's nest in parking lot an example of？A．A primitive type of nest.B．An e”相关的问题
What evolutionary change in birds led to nest building？
A．Their flying ability improved greatly.
B．They became warm-blooded.
C．They began to lay eggs.
D．They changed their migration patterns.
听力原文： Many egglaying animals merely lay their eggs and leave. With turtles for instance, the eggs hatch on their own. The current theory about birds is that the earliest birds did just that, when they were coldblooded creatures living in warm places. However when they became warmblooded creatures living in cold places they had to remain on top of the eggs to keep them warm. This process we call incubation. For this they needed a place, a nest very likely the first nests were just primitive depressions scraped into the ground. Even now many species still lay eggs in this sort of crude nest. In fact, every spring a mother killdeer lays her eggs in scene pebbles along the edged the parking lot just outside this building. Primitive nests on the ground were fine for some birds but others began to elevate their nests onto Branches, perhaps to avoid predators. These early elevated nests were probably loose platforms of sticks and twigs, the types still built by ospreys and mostarians today. The latest evolutionary development in nests the most re cent version, so to speak, is the cupshaped nest. This is the one we regard today as the typical bird's nest, you know, like a robin's nest.
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A．How birds' nests have evolved.
B．Why some birds' nests am considered primitive.
C．How birds learn to build nests.
D．Why birds lay eggs.
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