题干

如图表示光照强度和CO2浓度对某植物光合作用强度的影响。下列有关叙述中错误的是(    )

A:曲线中a点转向b点时,叶绿体中C3浓度降低

B:bc段影响光合作用速率的限制性因素可能是温度等其它条件

C:ab段影响光合作用速率的主要因素是光照强度

D:曲线中d点转向b点时,叶绿体中C5浓度升高

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答案(点此获取答案解析)

D

同类题3

阅读下列短文,从每题所给的四个选项(A、B、C或D)中,选出最佳选项

          Teens don't want to be seen with their parents, much less talk to them or do anything with them. That's what we hear all the time. I don't believe it. Oh,sure, when my daughter and my son were in their teens, they wanted to spend most of their free time with their friends. But there were always those special times planned when we enjoyed being alone with each other, when we connected deeply, and when we were reminded again how much we loved one another.

          I recall how delighted my 14-year-old daughter, Alisa, felt when I asked her for a date to see a movie. It was a bittersweet Italian movie, Cinema Paradiso, and I wanted this story to give her a sense of how I grew up as an Italian boy in a small town, where life was simple and where everyone knew one another. I wanted her to know how her father had been brought up and shaped.

          We both laughed and cried during the same scenes in the movie. She was attached to the movie. I decided we should complete our evening with some lively conversation at a nearby bakery. I told her the movie was now so much more special for me because I had shared it with her. She smiled. She understood. We made a memory that night.

          From our living room window, I saw my 13-year-old son, Jason, tearfully searching our vegetable garden for a place to bury his pet boa constrictor (蟒蛇). Because my son had suffered from asthma (哮喘) and allergies, he could never have  a dog, a faithful friend that he wanted so much. Every pet he owned—lizards, fish, or snakes—had died.

          I was at his side as we searched for the best gravesite (墓地). We dug the grave, said our goodbyes and then he cried. He cried hard and he asked me why every pet he had owned died so soon. I could feel his heart break against my chest. I just held him close. He let me hold his aching soul. He needed me while he was confused. Share your heart with your teens. Show them repeatedly that you know and love who they really are. There are tender memories waiting to be made.