单选题 As skies are filled with millions of migrating birds, European scientists say the seasonal miracle appears to depend on a seeming______: The fatter the bird, the more efficiently it flies.
【正确答案】 D
【答案解析】解析：句子大意为：天空中有数百万计的候鸟，欧洲科学家说这种季节性的奇迹主要体现在一个似乎矛盾的现象：鸟越肥胖，飞行效率越高。在给出的选项中：interruption“中断”；description“描述”；qualification“资格”；contradiction“矛盾”，该词与原句中解释性分句的意思相符。所以，正确答案是D。