题干

关于如图的相关叙述中,不正确的是(  )

A:若某植物幼苗已经表现出向光性,且测得其向光侧的生长素浓度为f,则其背光侧的生长素浓度范围是大于f

B:若某水平放置的植物幼苗表现出根的向地性、茎的背地性,且测得其茎的近地侧生长素浓度为2f,则茎的远地侧生长素浓度范围应为小于f

C:除草剂灭草的原理是使杂草的生长素浓度处于大于h状态下

D:若某植物顶芽的生长素浓度为g,产生顶端优势现象的侧芽生长素浓度是图中曲线的E点及E点以后区间

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答案(点此获取答案解析)

A

同类题4

根据短文内容及首字母提示,填写所缺单词,使短文意思完整。每空限填一词。

    Lan Lan, a student of Grade Seven in Lushan, was taking a drawing class in a tent on April 23. Guess what she drew—a house with wings. When the teacher asked why she did so, Lan said if her house could f____ , it wouldn't fall down in an earthquake.

    Lan's hometown was hit by a s____earthquake on April 20. At least 196 people were killed and more than 11,000 were injured. Many people became homeless. Soldiers and doctors q____arrived in the area, saving people and rebuilding homes. Lots of money was sent there to help all those in need.

    Although we can't prevent (阻止) an earthquake from happening, we can use some methods to r____harm. During an earthquake, do not jump out of high buildings because it is very d____. Another method is to cover your head and neck u____a strong table or desk. If there is no shelter (躲避处) nearby, you can also stay by a wall, and cover your head and neck with your arms and hands. And then you must keep calm and stay there u____ the shaking stops.

    Japan is a c____ which lies on the earthquake belt (地震带) and it is very good at dealing with earthquakes. From a very young age, the Japanese are already taught how to survive (幸存) them. Students often receive earthquake training. Almost in every Japanese family you can find a survival kit (救生装备) with a flash-light, a radio, water and enough food for several days. This helps people to stay a____after an earthquake.

    "There should be more safety t____at schools in our country," said Xu Jiannong, an education expert in Beijing. There is no more truth than this when one's life is the most important of all.