题干

下列有关植物矿质元素的吸收、运输和利用的叙述,不正确的是(    )
①植物叶片从幼到老的过程中,矿质元素有输入,也有输出;②土壤温度、通气状况和含水量等因素能影响矿质元素的吸收;③植物蒸腾作用为矿质元素的吸收和运输提供动力;④矿质元素只会出现在本质部的导管中,不会出现在韧皮部的筛管中;⑤K能被植物体多次利用,所以在作物生长过程中不用施钾肥;⑥Ca在植物体内不能被再利用,所以在作物生长过程中总要施用钙肥;⑦北方冬季气温低导致呼吸减弱,P难以吸收,但仍要在作物不同发育时期适量施P肥

A:①③④⑦

B:②④⑤⑥

C:③④⑤⑥

D:④⑤⑥⑦

上一题 下一题 0.0难度 选择题 更新时间:2019-11-28 09:28:59

答案(点此获取答案解析)

C

同类题2

      You either have it, or you don’t-a sense of direction. But why is it that some people could find their way across the Sahara without a map while others can lose themselves in the next street?
     Scientists say we’re all born with a sense of direction, but it is not properly understood how it works. One theory is that people with a good sense of direction have simply worked harder at developing it. Research being carried out at Liverpool University supports this idea and suggests that if we don’t use it, we lose it.
   “Children as young as seven have the ability to find their way around,” says Jim Martland, research director of the project. “However, if they are not allowed out alone or are taken everywhere by car, they never develop the skills.”
Jim Martland also emphasizes that young people should be taught certain skills to improve their sense of direction. He makes the following suggestions:
    If you are using a map, turn it so that it relates to(与……有联系) the way you are facing.
   If you leave your bike in a strange place, put it near something like a big stone or a tree-something easy to recognize. Note landmarks on the route as you go away from your bike. When you return, go back along the same route.
   Simplify(简化) the way for finding your direction by using lines such as streets in a town, streams, or wells in the countryside to guide you. Count your steps so that you know how far you have gone and note any landmarks such as towerblocks or hills which can help to find out where you are.
   Now you will never get lost again!