问题
选择题
下列哪些特征有利于鱼克服在水中游泳时的阻力?( )
A.身体呈梭形或流线型
B.体表覆盖着鳞片
C.体表可以分泌黏液
D.以上三项都对
答案
鱼的头部和尾部较尖,躯干部宽大,身体侧扁,为梭形,体表覆盖着大量的鳞片,能分泌粘液,比较粘滑,可以减少在水中的阻力,适于在水中生活.
故选:D
下列哪些特征有利于鱼克服在水中游泳时的阻力?( )
A.身体呈梭形或流线型
B.体表覆盖着鳞片
C.体表可以分泌黏液
D.以上三项都对
鱼的头部和尾部较尖,躯干部宽大,身体侧扁,为梭形,体表覆盖着大量的鳞片,能分泌粘液,比较粘滑,可以减少在水中的阻力,适于在水中生活.
故选:D
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