阅读理解

Ann：My hobby is reading．I can learn a lot from different kinds of books．But that's not the only reason why I like reading．The other reason is that there are many stories in books．I always lose myself in the wonderful world that books show me．So friends，why not join me in reading books?Let's have fun together．

Bob：I used to be a bit weak，but now I'm strong because of doing sports．I do sports every day，such as running，swimming and playing bail games．I keep exercising for at least two hours a day．Whenever I feel tired，I do sports．That can make me relaxed．Then I can study better．Doing

sports is really a great hobby．

理想状态下，用图一的装置来研究光照强度和温度对光合作用的影响，得到如图二两条曲线．请据图分析回答：

（1）图一中烧杯中的液体为____ ．图二中反映光合速率的指标为____ ．

（2）曲线A、B相比较，____ 的光照强度较高，判断依据是____ ．

（3）图二中X段的光合速率主要受____ 的影响；Y段的光合速率主要受____ 的影响．

（4）实际实验中，阳光照射下，开始时产生O₂较快，但两三天后逐渐减慢，主要原因是____ 

（5）如果玻璃瓶中缺乏M²⁺，叶绿素合成受阻，长时间后水草将呈现____ （色素）的颜色．