题干

在天气晴朗的夏季,将一健康生长的植株放入密闭的玻璃罩内放在室外进行培养.每隔一段时间用CO2浓度检测仪测定玻璃罩内CO2浓度,绘制成如图所示曲线(水平虚线表示:实验开始时玻璃罩内CO2浓度).据图得出的判断中错误的是(  )

A:FG段表明气孔关闭,光合速率明显下降

B:E点时光合作用与呼吸作用的强度相等

C:影响曲线BC段变缓的主要因素是温度

D:植物体内的有机物经一昼夜有所增加

上一题 下一题 0.0难度 选择题 更新时间:2019-12-05 01:37:40

答案(点此获取答案解析)

B

同类题3

阅读下面短文,从短文后所给的A、B、C、D四个选项中, 选出可以填入空白处的最佳选项

    “It's nice having a friend,” said Mole (鼹鼠) to Rabbit as they sat talking in the sun one day.

    “Oh, it is!” said Rabbit.“Very useful, too, 1 if you need help. 2, I think I'd like Bull(公牛) to be my friend.”

    “But I'm your friend!” said Mole, feeling 3.

    “Oh, yes,” said Rabbit.“You are good for talking to and laughing with, 4you are too small. When I need help, I 5 someone big and strong like Bull.He would be a very good friend to have. It would be 6 shouting for him when I need help.”

    Mole went off in anger.

    “Oh,well,I need to 7 something,” Rabbit thought.

    He moved along 8 he found a tiny garden.He had just started on his first leaf when there was a big 9. People were shouting and dogs were barking(吠叫).Rabbit was so afraid and in such a 10 to get away that he ran into the wrong hole.

    The hole was too 11 and Rabbit got stuck(被卡住).He could not 12 at all.

    “Help!” cried Rabbit.

    Mole 13 him.He ran up to see what was the matter.

    “Help!” cried Rabbit.“I'm stuck in this hole.”

    “If you want help,” said Mole,“I'd better 14 Bull.”

    “No!” cried Rabbit.“He's no good! He's too big to get into this 15.You're just the right 16! Please help me,Mole!”

    So Mole began digging around Rabbit.He 17 so fast that Rabbit was 18 soon.

    “I'm sorry, Mole.I was 19,” Rabbit said.“I'm 20 I have you for a friend.” And so the two good friends set off for home together.