Airline pilots have various aids to guide them on their journey.
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Scientists have found out how pigeons find their way home but they keep it as asecret.
A. 对
B. 错
It’s certain that pigeons, like airline pilots, have various aids to guide them in their long-distance flights.
A. 对
B. 错
食物因素中,对致龋最有影响的物质是____C.蛋白质B.乳糖A.蔗糖E.氨基酸D.维生素
目前龋病发病学说中为大多数人所接受的是()
A. 酸原学说(化学细菌学说)
B. 蛋白溶解学说
C. 蛋白溶解-鳌合学说
D. 四联因素学说
E. 内因学说
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