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According to paragraph 6 which of the followi
问题详情
According to paragraph 6, which of the following is true about the wings of birds？
A．All birds flap their wings constantly by using breast muscles.
B．Eagles and hawks have wings that propel them at 170 km/hr.
C．The airfoils of birds function like the wings on airplanes.
D．Wings are attached to airfoils in the bird"s skeletal structure.请帮忙给出正确答案和分析，谢谢！
参考答案
正确答案：C
解析："Bird wings are airfoils that illustrate the same principles of aerodynamics as the wings of an airplane." Choice A is not correct because some birds flap their wings only occasionally. Choice B is not correct because swifts, not eagles and hawks, can fly 170 km/hr. Choice D is not correct because the wings are the airfoils, and they are attached to the sternum (breastbone).
