题目

植物茎产生向光性是因为A. 单侧光照促进生长素合成B. 单侧光照抑制向光侧细胞生长C. 单侧光照引起生长素分布不均D. 单侧光照使背光侧生长素合成加快 答案：【答案】C【解析】据题文的描述可知，该题考查学生对植物的向光性形成的原因的识记和理解能力。植物茎的向光性形成的原因是：由于单侧光照射，茎的背光一侧生长素含量多于向光一侧，引起两侧细胞的生长不均匀，使背光一侧生长快，从而表现出弯向光源生长，C正确，A、B、D均错误。These companies succeeded because they were the first companies to make use of the ____________ of the internet and was thought highly of by some experts.A．potentialB．possibilityC．prejudiceD．precious