题干

近年来大气中的CO2浓度和O3浓度不断上升。为了研究CO2浓度和O3浓度上升对农作物有何影响,研究人员用高浓度CO2和高浓度O3处理水稻“汕优63”,测定其生长发育不同时期的各项生理指标,结果如图。下列叙述错误的是(    )

[注:CK(对照,大气常态浓度);CO2(CO2常态浓度+200μmol·mol-1);O3(O3常态浓度×160%);CO2+O3(CO2常态浓度+200μmol·mol-1和O3常态浓度×160%)。表观光合速率是指在光照条件下,一定量的植物在单位时间内吸收外界的CO2量。]

A:实验结果表明,不同生长发育时期,升高CO2浓度,水稻的表观光合速率增大

B:高浓度CO2可部分抵消高浓度O3对水稻光合作用的胁迫

C:水稻表观光合速率的增大可能与胞间CO2浓度升高有关

D:实验结果表明,O3浓度降低会危及水稻的生长

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答案(点此获取答案解析)

D

同类题3

阅读下面短文,从短文后各题所给四个选项(A、B、C和D)中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。

    A group of frogs were traveling through the woods, and two of them fell into a pit(深坑).When the other frogs saw how 1 the pit was, they told the two frogs that they2as well wait to die. The two frogs ignored the comments and tried to jump3 the pit with all their4 The other frogs kept telling them to5,and that they were as good as dead. Finally, one of the two frogs listened to what the other frogs said and6.He fell down and died.

    The other frog continued to jump 7 and try his best. Once again, the crowd of frogs shouted at him to stop the8and just die. He jumped even harder and finally9 it. When he got out, the other frog said," Didn't you 10us?" The frog explained to them that he was a little 11.He thought they were 12 him the entire time rather than advising him to stop the pain of struggle.

    This story teaches us two13: First, there is the power of life and14 in words. An encouraging word to someone who is15 can lift him up and help him make it through. Second, a(n) 16 word to someone who is down can be what it takes to kill him.

Be careful of 17 you say. Speak positively to those who cross your path.The power of words is so great; it is18 hard to understand that an encouraging word can go such a(n) 19 way. Anyone can speak words that tend to rob(掠夺)another of the20 to continue in difficult times.The individual who will take the time to encourage another is special.